I use both, chrome supports WebGL which is needed for Scratch, also Writefull plug in for Overleaf needs chrome.
Having the option is useful.
Good idea on keeping them sandboxed, I dumped Twitter in November, stopped using FB decade + ago.
I appreciate people need them despite what goes on with data or in the case of twitter all the hate.
Hopefully fedi will be more of a space space for people so they CAN move over slowly.