Sometimes people build things just because they want to. Some people will take a look and say “hey that’s cool” and use it. Some others will take a look and say “this does nothing for me” and both are valid opinions to have. IMO nobody should have to justify an open source project unless asking for funding.

Wine already exists and can run pretty new Windows software. A fork also exists for MacOS and the other BSDs can also run Wine.

Running Windows apps on Linux natively seems impractical to me, the OSes are structured very differently and I’m fairly sure this would introduce many hard to fix CVEs.

ReactOS does actually submit patches to wine sometimes because they use parts of wine! But they have their own windows-like kernel so they only need wine for userland, not the whole thing