I have a digital keyboard that has a transpose function which can shift the pitch up or down by the number of semi-tones I want. I hear some say that most good keyboardists frown up using the transpose function.

I understand their reasoning - that to be be considered a proficient player one has to be comfortable with all scales. For eg, on the occasion that I am provided with an acoustic piano there would be no transpose option. But my counter argument is that, as long as an enjoyable music is produced, should we really care if transpose is used or not. In some sense, aren't chords on the guitar 'transposed' from the previous keys down the fret board? the chord shapes look pretty similar, just at different points on the fret board.

It may seem I am arguing in favor of using the transpose function, but I might be missing a whole lot of perspective. Curious to know some additional insights for and against.