That's exactly what I do, along with raising my hand in the air if I'm trying to get air INTO the gloves. I usually have more problems on ascent, trying to get it OUT.
That right there is the best reason to use something to help vent the glove on descent and on ascent. Coming up with one hand looking like Mickey Mouse hands is kinda funny, but two hands could be an issue. Say for some reason you were required to perform a controlled rapid ascent while performing tasks?
I don't like using the thumb loops, because if you flood a glove, you have to try to tuck the loop back under your wrist seal, and in the process, you're likely to let in a lot of water. I use pieces of IV tubing, when I use anything, because it's soft and flexible, but hard to collapse. Mostly, I've found that the prominent tendons at my wrists allow my gloves to equalize most of the time without me doing anything special.
I have had great success with the thumb loops and have successfully pulled them back twice now!
Since the thumb loops get used to put the suit on, what I do is then release them from my thumb and retract them, until they are barely visible under my wrist seal. Like maybe 2mm sticking out.
Here is an excerpt from a previous post of mine about a dive at Gerstle Cove.
Once at the outer part of the cove I took a heading and set both my compasses. I mostly use the one mounted on my scooter though. Dropping into 30' of water the vis is decent with around 15' horizontal. As I head out the cove further it starts deteriorating quickly. I am cruising along looking down and when I look up again I see fishing line. Oh snap! I get off the trigger, flare my feet, and put my left hand out. At this point the fishing line is going behind me, but it is still in my hand. The fisherman on shore probably yelled, "HOLD MY BEER I GOT A BIG ONE!"
Here they are fishing for ME! Sorry for the bad photo they are a long long way off. You can see the rock outcropping, across the cove, in the photo above.
I made a quick decision to try to break the line as quickly as possible. Tossing my scooter aside, I grabbed the line with my right hand and pulled my hands apart quickly breaking the line as I can feel the fisherman pulling me towards them. Now I have line running across my back that I can't see. I stop and gently helicopter around but the line follows. Oh no...the hook is set? I roll gently with the line in my hand and find I am not hooked, but there is a spark plug moving in the sand as I tug on the line. Big relief
I never panicked but reacted when the line was moving quickly past me and the thought of the hook set me in motion quickly. Once that was out of the way I slowly worked myself free. There isn't much I could do with the fishing line, but I wasn't about to leave a baited hook on the bottom. I removed the bait and then took the hook and ground the tip on a rock, eventually removing the spark plug with my cut off steak knife and sticking it in my pocket. During this time I notice the cold water getting into my left glove.
When I get myself squared away I start inspecting my glove. Sure enough on the pinky finger there is a nice slice from the fishing line. The water is warm at 50 degrees, but not something I want in my dry glove. Every time I bend my finger more cold water rushes in. Since I use my under garment thumb loop as a "straw" under the latex seal, for equalization, I decide to try to pull it out so only my glove will flood. I have done this before when I punctured a glove wearing my CF200. Now I am in a Fusion though so I have to go through two layers of drysuit. Like any PADI trained diver the first thing I have to do when performing this drill is kneel on the bottom. Well in this case it was sand, and I needed my arm up high to fill it with air. Dumping the wing set me on the bottom, then I closed the drysuit exhaust valve and pumped a little more air into my suit. Having the arm blown up like Popeye's arm, I was able with a little fiddling to think I had the thumb loop clear, but time would tell. After resetting the exhaust valve and adding air back into my wing, I set off again, this time with a cold wet hand.
(It didn't leak past the wrist seal, so I only had to contend with a slowly leaking glove)