I might do a song in Db, but only to make it fit my voice. If so, I would probably use the transpose button, to make it easier for me.
I don't worry about making jazz songs, or any other songs, sound exactly like everybody else has done them since they were written. Probably couldn't if I wanted. It would be easier to play a recording of the real guy!
I guarantee that my audience does not know what key I'm playing in, except if Rory or someone else with perfect pitch were there. And then, I wouldn't care if they cared!
Use all the tools at your disposal as you wish to use them to make the job easier and better.
DonM