I second this. I'm agree about the X as an app closer when the app is used as a standard application that you use like chrome, notepad, excel, etc. It's different with apps like discord, teams, docker desktop, open vpn (listing my tray apps hehe) etc, Where you use it and close it but expect that it keeps running in background on tray. Easy access to the close button on this kind of apps has the risk of closing it an miss the service they provide.
I think obs could fit in both scenarios. If you use it for broadcasting, I guess you will always keep opened until you dont need it anymore and the close button ensures you that you stop the broadcast and the app is no more running.
In my case I use it for it's virtual camera and audio mixing capabilities and use hotkeys to change scenes (me, me closer, my screen shared, etc). So in this case, obs is working more like a background app, like the one I mentioned, and it's expected not to die when I press X.
So, please... Give us the choice to enable this behavior. Thanks!