This will limit their usefulness to very specific round trips or small clusters...
Then it's clear I missread it...
I'd suggest you to specify it to avoid others to do the same
Except for perishable/urgent cargoes and passengers...
Higer jumps allow you to be more picky in your ports of call, and to carry those cargoes too (probably for a premium price, mostly in speculation), while, if, as you sway, they carry collapsible tanks in their cargo space, they can use their full cargo when performing J1.
Even if freight paid per jump, and so double for 2 jumps, speculative cargo (one of the main source of income in most merchants) goes per Port of Call, and while calling every 2 or 3 jumps (as you suggest) may give you the same money for freight, it will not for speculative cargoes.
I'd also put some staterooms for passengers if they are for regular schedules, as they give you some more money per ton than freight if they are full, and if they mostly jump among decent population worlds (as they are the ones with better starposts, as I understand from your comments, they are likely to be full at most jumps.
In general, I see it a useful design for such adjacent (or even at J2, less so at J3) pairs/clusters of planets with good starports, but not so good as adventure ship.
So, a good background ship, but not the one I'd like to have with my character (personal opinion, of course, YMMV). Some staterooms might also allow (from gaming prespective) to be the scenario of an adventure itself, if something happens on it while the players are its passengers.