OFC, but we need boxes to turn into celestials when that happens anyways.
I see what you mean. Right now in the early levels of the skill we don't benefit much from saving things up, but the higher our max skill level the more and more boxes we'll want to have on Calliope all at once. From that angle, Moose is a box bank, able to hold a Celestial's worth of boxes until we have enough to send them to Calliope for the big rollup.
Though that said, it's just as easy to move boxes onto Moose as it is to move boxes off of Moose, and the sooner we get Wheeler Dealer up to level 2 or 3 the sooner we can start getting Golds and Platinums out of it. Unless 6-hour windows where we don't need SysOp are vanishingly rare (we still need sleep, right?) we'll have ample opportunity to fill or empty box banks as we please.
Picture it like this: we have two routes we can take for an individual Bronze box. Either we keep it in the box bank until we're ready for a celestial, or we open it now and find another one later. Neither option changes the
total number of boxes we need to acquire, because keeping the Bronze in the box bank means we need to find one more Bronze for the level grinding, but rolling it up now gives us the benefits of the early level grind now instead of later.
If we're talking sentimental value, letting Moose keep his hard-earned boxes until he has the intelligence to make an informed decision on what he wants to do with them, then that's a fine stance to have. But if we're talking optimality, there's simply no benefit in leaving the boxes in a box bank.
(side-note, but when we do use Wheeler Dealer we should try to use SysOp to make sure that Calliope has
exactly enough for the highest-rated box she can roll up to. If she can roll up to 2 Platinums but then has one Bronze leftover, that Bronze is wasted compared to its potential value as part of the next Platinum, so we should have it moved over to one of the box banks. Or rather, when Taylor sends all his boxes over to Calliope, he could hold that Bronze back so Calliope lands at exactly the right amount for some integer number of Platinum boxes with no remainder. That sort of thing)