"Restoring" worn detail is another issue. If that is done, it's a big deal for any coin in my opinion. For ancient coins, lightly smoothing fields or scraping off corrosion seems to be acceptable. Here's an example. This AS as had a lot of work done on it.
The answer is: it depends. It depends on what you want, are willing to tolerate and/or what you think you are paying for. A collector paying “full retail” plus fees deserves a fair description. I’m not sure the original coin in this thread counts as full retail and was discounted because the cleaning work wasn’t exactly The British Museum quality.
How much "British Museum" quality stuff do you see these days? I have bought a couple denarii that might qualify, but when it comes to copper, there not much.
Classic adage - just because it's in a museum, doesn't mean its good. My uncle is a film producer in China; he started off making extremely detailed film props. Every time we go to a museum in China, he will point out the fakes in the display cases; the real ones are often somewhere down in the basement.
I am curious how this applies here. IMO the British Museum specimen is by far the better of the two because the other was scrubbed, scratched and polished. All ancient coins have been cleaned but being cleaned is not the same as being destroyed.
The previous response demonstrates why I avoid buying ancient coins in copper. I am too old to figure out this riddle. For American coins, the British Museum piece would be in a copper coin in a junk box. To be objective, the first piece would be in a “details” third party grading company holder. I am not venturing into that confusing territory. I’ll buy silver, higher grade silver washed coins, smooth unprocessed looking copper and some day, I hope, gold. I might add that there are purists in the field of American gold coins who think that gold coins that look like copper have “character.” Some of them only have a coating of iodine.