hi,
personally, if either of my sons had been interested in music, I wouldn't have encouraged them to play an arranger keyboard. I would have much preferred they took up piano or guitar or whatever. The younger one did learn guitar for about 6 months, but he was far more interested in playing sport.
As for myself, I was 20, and way too old according to my piano teacher , to ever become a decent piano player. I just wanted to be able to play the odd tune for self entertainment. 15 years down the track, along came the arranger keyboard & I was conductor, soloist & backing band all in one.

Still think a child should be taught a traditional instrument rather than an arranger keyboard. Also seems like a lot of the pro players using arranger keyboards, may have actually learnt and played a traditional instrument in the beginning ??

best wishes
Rikki