When I first started studying music - on accordion - there was no transpose key, so I had to play in all different keys ...
I knew an accordionist who played in the 'block chord style' of Art Van Damme, and could play any standard in ANY key ...

For the most part - maybe 90 - 95 % of what I play is in the key I sing in or in the key the song was written (or published) in ... There are a few songs that I think sound better in certain keys, i.e. "Misty" in Eb which is out of my vocal range, so I play it as an instrumental ... if there is a request for me to do it as a vocal, I will use the transpose key ...
There are a few songs that I have set the style for with transposition to another key ... This can cause some confusion if playing with another musician and I call out the key that's on the music and I forget that I've transposed it to my vocal key ...
TO ME playing in one key all the time would get boring, but that's ME ... do whatever suits YOU best ...