Yes, I realize that since the BattleDome is turn-based Movement doesn't have that large an effect. And generally speaking, BD pets are measured with HSD (Hitpoints, Strength, Defense), correct? I've heard that the only time Movement is actually useful is for a few equips that have it as a stat requirement...? What equips are these? (So I can see if they'd be worthwhile to invest the codestones, and of course NPs, in.)
Heavy Robe of Thievery is one of the items that comes out of my mind. I believe there are some others as well.. but only a few more.
If you're going to do SP, HRoT is extremely helpful. Then again, it's very expensive to train that much. It's probably not worth it.
Technically its useless, though there are equipments that require some points in movement, I don't think your final battling set will include them. Unless somehow TNT introduces a new use for movement stat then that would be pretty unlucky :/
Anyone remember the Lost Desert plot a couple years back? Moving the blocks of sand required movement IIRC, so there may be the occasional use for site events too.
You said it. I think it'll take a couple of years again before there's something where you need the movement. But I think, when the times comes, you can probably lend a pet from someone else.
No need to train for movement. If you ever get to a high enough level to need equipment that requires it, you'll already have started negging. Many many of the training neggs give movement in addition to whatever main stat you want to train, so you'll end up with plenty of movement in the end.