Avengers: Endgame spoilers ahead. One of the things that made Thanos such an interesting villain in Avengers: Infinity War was that he actually did what he said he was going to do — quickly. With a snap of his fingers and no hesitation, Thanos wiped out half of the living creatures in the universe. But, um, how did he do that? How do you control the Infinity Gauntlet? Was the snap really necessary, or was that more to prove a point? Like, "I can do this with a snap of my fingers"? Which he did!
Based only on the information we get from the films, it seems that a gauntlet is not strictly necessary. The power comes from the Infinity Stones themselves, and to use the stones to their full combined power, the user has to be in possession of all of them. The gauntlet is a way to conveniently keep them on hand. Literally.
In the MCU, a gauntlet is seen in the first Thor movie, but later in Thor: Ragnarok, it's explained that it's a fake. So, there is a history as far as a gauntlet being what's used to house the stones.
And a gauntlet would need to be very strong to be able to contain the stones' power, which is brought up when Thanos's own gauntlet is talked about in Infinity War. In the movie, a weapon maker named Eitri explains to Thor that he made the gauntlet for Thanos after the big purple guy threatened his people. "I made what he wanted," Eitri says, "a device capable of harnessing the power of the stones. And he killed everyone, anyway." The fact that Eitri came up with this design suggests that it didn't have to be a gauntlet, specifically.
It follows, then, that the snapping was unnecessary, right? Infinity War and Endgame are based in part on The Infinity Gauntlet comic miniseries by Jim Starlin, and he spoke about the snap, which is original to his story, in an interview with Mashable.
"It seemed the most dismissive gesture that I could come up with at the time," Starlin explained. "I wanted something casual, but something that would have a hook to it. I never in a million years imagined it would become this pop culture moment that it has become. But it was basically a contemptuous way of executing what he was planning on doing at the time. And it looked good with the gauntlet."
Thanos is psychopathic in that he has a huge ego and doesn't feel an ounce of remorse about killing half of all life. This is the kind of person — well, Titan who would want to boast that he could achieve his goal with a simple snap. It's something his "daughter" Gamora talks about in Infinity War.
"The entire time I knew Thanos he only ever had one goal: to bring balance to the universe by wiping out half of all life," she says. "He used to kill people planet by planet, massacre by massacre. If he gets all six Infinity Stones he can do it with a snap of his fingers, like this," she concludes with a snap.
In Endgame, it seems that the heroes can control the power of the stones by wielding them all together and just thinking really hard about what they want. When Bruce snaps his fingers, he brings everyone from the past back without changing the present, as Tony emphasizes. And when Tony later snaps his fingers, he turns Thanos and his armies and ships into dust, not a random half of the universe.
So, the actual control of the gauntlet seems to be more mental: If you have all the stones, you are so powerful that you can will things into happening with your mind. A gauntlet is an intimidating way of carrying the stones, though, and keeps them pretty safe. And using a snap lets the audience physically see when the stones are used, rather than it just happening in Thanos's mind. Guess that's why the Avengers followed Thanos's lead and went with making their own gauntlet rather than, say, the Infinity Fanny Pack.