If it's sitting on a shelf... no.
If it is being moved in any that might cause jarring or rough handling, then I would say it's a good idea for the same reason you wear a seatbelt while underway in a moving vehicle... you might not need it, but if you do you will be glad you had it on.
Think I read this somewhere else and I forgot to remove it on my first flight; but then I just grabbed the marker and the same way I numbered the batteries, I just wrote "gimbal" on top of the power-on button; I'd say muscle memory will do the rest; before I had to spend money on a red ribbon, I'd use those 5e for petrol instead
I would not say it's "necessary" ... but it's a REALLY GOOD thing to do keep your gimbal from flopping around (even with the dome on) while it's being transported around in your case. Let's put it this way ... It doesn't hurt!