The more I play my DGX 650, the more I enjoy the benefit of 88 weighted keys in an arranger.

The ability to instantly play different octaves for not only piano but also voices other than piano(brass, woodwind, strings etc)is a big deal. Different octaves produce distinctly different voices.

As an acoustic guitar player, I love the ability of being able to use(simulated..yes I know)hammered action to change the dynamics of the voices.

I'd probably gig with an 88 key (simulated)hammered action piano if I didn't have to use a front end loader or crane (because of weight/size) to move the instrument from gig to gig.