> Their argument is that all team members should use the same tools, and I guess that is a valid point.

Not really. If they mandated all team members use telnet instead of ssh, would you say their position is valid?

Anyway, the important thing to learn is "You're not supposed to ask if you can use Emacs. Just use it!"

Incidentally, do they have a mandated general text editor? And if they do, will you get in trouble for firing up Notepad?

Do they have a mandated TODO tool (for your own tracking of work, not something like Jira meant for the whole group)? I've yet encountered a place that did.

Basically, find some category that Emacs does that they've not mandated, and then install Emacs and tell people you're using it for that category :-)