You can, but plugging thumb drives into work machines is not always kosher

One of the uses of notepad was also that it’s installed by default, and was a place you could be assured wouldn’t mess with your text. No formatting, no weird characters you didn’t ask for.

Notepad++ is great, but you can’t be assured it’s installed on any arbitrary Windows machine.

If those are communication apps supported by the bank, that’s the idea. Banks have been hit with huge fines for employees communicating over unapproved channels.

One of the problems with the unapproved channels is that the bank can’t enforce a retention period. So written messages that are supposed to be kept on record for 10 years or whatever can get deleted. In the event of a lawsuit the bank can be fined for not having the messages.