Honestly, # and * on the dialer are mostly anachronisms from another era. I haven't heard "press # to continue" in ages, everyone uses numbers now. ("Press 7 for STFU")

As for "hashtag minor", it's a reshare of a second-person story, so I trust it about as far as I can throw it.

As several people have commented, it's common on phone conferencing systems, when entering the conference code "followed by the pound sign".

It's also used to check Verizon FiOS voice mail, where you enter it after entering your PIN.

As for the *, up until recently, I had a voice mail system where you used it if you were checking messages from a phone other than your own, to signal you'd be entering a phone (non-menu) number.

*...# is at least in Europe is used for many functions when you call it (e.g. topping up your prepaid phone, showing your balance)

You have to use # to get into a variety of phone conferencing systems, banks, and other stuff - it's the defacto "end of number" character at least here in the UK (e.g., "Enter your conference pin number, followed by the hash").

Haven't seen/heard of a use of * outside local PBX in years though.

As that’s stored on a hard drive somewhere, you can probably stick that on a flash drive and throw it pretty far.

I was listening to a podcast once where people were saying "C number". It took me a long time to realize they were talking about C#.