Why not? If the saxophone sounds realistic and you can play it on a keyboard to make it sound realistically accurate as far as how a saxophone should be emulated i.e. like a live saxophone player would play it, then go for it! The T4 has probably the best saxophone voices of any arranger but the trick is to play it on the keyboard in such a way as to make it sound as realistically as possible to how a real saxophone player would play the instrument. Which, needless to say, is very difficult to pull off on a keyboard with a 'sampled' voice while trying to emulate all the nuances and other things to make it sound authentic. Although if you're playing at Senior Centers or other less informal venues then "fairly authentic" is probably good enough.

All the best,
Mike