Although my plugins usually work the same on Windows/Mac/Linux, I have to be careful.
My plugins are Metahuman based, so there are some dependencies for Metahumans that do not work on all platforms.
I decided at the beginning to test on all target platforms just to be safe.
I have had support requests that ended up being platform specific issues.
One of the engine versions of my plugin would not package on Linux but did on Windows/Mac.
Without debugging in Linux, I would have not been able to solve the issue and then the customer would have been entitled to ask for a refund.