"Is it OK to use the transpose button on an electronic keyboard?"
I get this question a lot. And yes, it's a good question: Transposing music from one key to another is difficult at first and pushing that transpose button is pretty easy, right? Is it OK to use it?
Yes, it's OK to do sometimes. But at the same time, it's also very valuable to practice transposing on the piano or keyboard, learning how to transfer a melody and chord progression from one key to another. Even though it's difficult at first, the act of transposing helps us become a much better musicians and understand music better. It forces us to see relationships between chords, both within one key and between two different keys. It's also an invaluable exercise for training the musical ear.
Yes, practice transposing. When I was about 16-17 years old, I would practice playing easy classical pieces in all 12 keys. Later, I moved on to pop and jazz songs. Them Charlie Parker licks.
When I'm rehearsing or performing, especially with vocalists who need a song playing in a higher or lower key than what's printed in the sheet music or chart, I prefer to transpose it myself. But sometimes the music is too complex for me to play it accurately in the new key without practicing it ahead of time, so I'll sometimes use the transpose button on the keyboard. (This won't work, of course, on an acoustic piano!)
The only problem for me is that sometimes I use the button and unconsciously transpose the music as well, so it ends up being in a totally different key than I intended. It's always a funny moment for me when I suddenly realize, about halfway through the piece, that I have no idea what key I'm actually in!!!