If the decision comes down to "I can't get the exact shade of cornflower blue I want on this button unless I make it a div, but that will hurt accessibility" and you chose the exact shade of cornflower blue, your priorities are wrong. And not just because you hurt accessibility, but because you probably made more work for yourself.
We went through this 15 years ago with custom scroll bars that didn't look like scroll bars, didn't operate like scroll bars and didn't interact like scroll bars, all because it could happen. An Ian Malcom quote comes to mind.
I don't think that's a conscious decision though. What happens is:
- I can't get this exact shade of cornflower blue
- Oh, here's a solution that works! Oh, it doesn't work in all browsers
- Hmm, here's a stack overflow answer that says use a div. It's 5 years old, is that current? Dunno but it has 457 up votes and works
Some people are concerned about accessibility but the JavaScript doesn't work in iOS. Others have iOS support but they screwed up cache headers and it's super slow on any low bandwidth connection.
Balancing all those things (and that's a very incomplete list) is hard and it's not fair to expect side/hobby/oss projects to do it 100%.
Huh? You can get whatever shade you want. Just use a reset stylesheet for buttons and then you can style them like you would any other div. They work in every browser, too. I understand the argument that a decade ago this was trickier, but that time has long since passed. Style your button with css.
We went through this 15 years ago with custom scroll bars that didn't look like scroll bars, didn't operate like scroll bars and didn't interact like scroll bars, all because it could happen. An Ian Malcom quote comes to mind.