Yay or nay
It is a difficult one really, I would label it as a decent opportunity and good alternative to paying for the rating, although 18 months does seem like alot a year would suffice surely. Having worked as a flight dispatcher I think getting that exposure is a good way to give future FO's the ground experience to actually appreciate the people you are going to spend your career alongside - cabin crew/gnd handlers/engineers.
However, the simple fact is that those hired last year didn't have to do this and I would guess you only start working off your bond once it has been 'paid' i.e it dosent include the 18 months you just spent on the ground.
In that context its a **** deal but still unfortunately probably the best thing to come along in awhile, clever stuff from Jet2 really