Well, that solves ONE small problem (and they have a few of those in the Roland's too). Now tell me how you do the same bend quietly? Or slower (it's sampled)? And on ANY sound?

Next figure out how to either do it as a true 'bend' or the sampled fret-slide (which is what it is).... You begin to see the staggering range of different articulations real instruments can choose from. A bender can only do so much. For hammer-ons and offs, trills, tongued/legato phrases etc., a pitch strip (like Korg's, Kurzweils, old KX-5 strap-on controllers, etc.) are another choice.

But no sampled, velocity triggered 'effect' is going to allow for 'true' expression, just a poor imitation of it.