A few possible worms for the can:
* It would seem unlikely that the organisation could require crewies to undertake this training if they don't want to, as it's not just professional development within a role, but a whole career change, in effect.
There may well be people who have good legitimate reasons for not wanting to get involved, and it'd be their right to say no.
* After a few years, there'll probably be crewpersons/copilots jumping ship to further their pilot careers, draining experience from the organisation.
* What happens to those who commence pilot training but don't finish for some reason? Will they have to pay the company back the money spent on them?
* Having someone fill a dual copilot/crewie role puts extra pressure on them and, in my opinion, would tend to reduce their effectiveness compared to having people employed separately as copilots and crewies.
As I said previously, I'm not involved in the organisation, but I can't see too many benefits to this scheme on the face of it.