I'll add in addition - the skeumorphism here is generally pretty functional, you touched on this when you said "everyone is used to them"

But the layout of these buttons, while certainly not standard, is generally familiar across various filters, etc. So if you are dealing with a complex interface the skeumorphism absolutely helps to make the input more familiar and easily accessible.

This is what skeumorphism is for and this is a great place to use it.

Imagine if the symbols for "play" "pause" and "stop" were changed simply because it no longer made sense to follow the conventions of a VCR, then multiply that by an order of magnitude.