Playing chords in all keys is easy with guitar. Guitar melody solos fall better in some keys.

In my pro keyboard days, I played songs in their original keys; transposing for a singer was not a problem. The first twenty years we never used a music on stage.

In the past three years I got lazy; it was easier playing everything in C. There is an up-side to playing everything in C, chord progressions, fill inns, and chord substitutions become second-nature, you do them without thought. In short you play the songs better in C.

I have a new friend, he plays all songs in F# ????? Must like the black keys. Bottom line; his playing is far above average, He Is Good.

Just saying, John C.
PS, are there any guitar players here who would like written melody for guitar?
Many years ago at my daughter’s wedding, the ceremony stopped so that I could play their favorite song: “What are You Doing the Rest of Your Life”, no backing, just guitar playing melody chords.