I consider the prices you posted to be the value of those objects at that shop, since that is how I would trade most silver, even though I purely buy for fun. I mainly like to do futile things like look for nice old or rare coins in pocket change. I typically use debit and hardly even have coins.
I do understand the difference between rounds and currency coins, for one thing it's unlikely a round will fetch the ridicules prices an actual quarter or even a penny can, currently or in the future. My point was high grade or just nice rounds are more valuable than spot value bullion currently. Even some bullion bars have added value to collectors.
I am very conservative so I would buy junk coins for investing any significant amount of money because they are easy, I can buy it at the lowest price based on silver weight and they will never lose value by becoming, tarnished, bit by a crazy person, milk spotted, cleaned, bent or scratched. I like that I can't ruin them. No matter what I do, they are still worth the same price and it is solely based on their weight. Conversely most people would buy new rounds/coins since they hope to keep them nice so they will increase in value (price).
If I buy two new rounds and store them for a few years, one stays shiny the other gets milk spots, they hold the same value to you but I would try to find someone willing to pay more for the one without spots. In my opinion it has a higher value if I can get more money for it during sale and I like more money. Milk spots are a legitimate fear as far as I am concerned. if you bought anything for $60 then it gets spots and becomes worth $20. I consider that to be a significant loss even though $40 is not enough money to buy a good bottle of whiskey.
Here is a Crocodile, I think they are rounds.https://www.apmex.com/product/83319/201 ... ocodile-bu
I believe the 1oz Perth mint .999 silver comes in Crocodile, Koala, Kangaroo and Kukaburra. There might be more.
As tzor wrote, there is added value to a round made by a particular source. To me that makes certain rounds such as Maple Leafs, Eagles, Pandas, Elephants etc. a coin since it is a legitimate national mint product and not something tzor and I made from melted silver butter knives in a shed. We could make rounds and even stamp them .999 but the coin shop is probably only going to buy it as junk silver. They will pay more for a milk spotted Maple Leaf and even more for an MS64 Elephant.
Unless you rip someone off you almost certainly won't sell a maple leaf even graded MS70 for several hundred dollars. The right old error penny even in lower mint or circulated state might be valued over a thousand.
Getting coins graded is interesting. I watched a video about graded state coins. The guy makes a great point, sending in a quarter for grading takes courage.
Grading is somewhat subjective. You can send a slab in to get re-graded and sometimes they go up, sometimes they go down. I have watched several videos, these guys are very experienced but they don't know how a coin will grade until it comes back. An MS67 could be worth $100+ and an MS64 is worth $20, it costs $30 to get it graded.
Getting an object I bought for $32 cdn graded by PCGS for $30 us is pointless if it returns a mid or low grade and is still worth $32 cdn. One thing that made maple leafs valuable as you know is they come in a sealed capsule from the mint. That is why milk spots are so bad, they are one of the things that can happen to change the appearance of them inside a sealed capsule stored in a drawer or safe.
Having said that silver could go up in value enough that an ouch of silver makes it worth the same thousand dollars per ounce as junk silver. At that point the extra value of a premium graded coin would be tough to get since anyone that could afford it would already have bought what they wanted.
I think the face value of most silver currency coins has become pointless. I certainly agree the mints are gouging people by over pricing coins sold at the post office. Here's a $5 coin with a half ounce of silver $69.99. Also an old silver dime or quarter is not really what it was made to be anymore because even the melt value is more. That is why they are called junk silver if they are improperly cleaned, they might even be really nice but are ruined by cleaning. I'm pretty sure that is part of why people suggest boiling them as a good way to clean one without "damaging" them. They are now with less. That will increase the value of the original condition coins that are not cleaned.
The only way I can imagine buying a high value collectors coin would be if I made some money from trading junk silver or something.
I bought the koala because I had some money from Christmas and I wanted a kangaroo but they were out. It was less expensive than a baseball hat. I was going to buy a maple leaf but I might not because of the risk of milk spots. I might one day because I like them and I would like an eagle.