They’re not stuck in Overwatch miles away.
The advantage of doing this rather than spending both action points is that, if your third person comes across a group of enemies, you still have an action point spare on the first two soldiers. Everyone has two action points, but you don’t have to use both at once – you can move one person with their first action point, then switch to a second person and move them, then switch to a third person and move them, etc. When you’re not actively in combat, try to stagger your squad’s movements. Cover, whether half-cover or full-cover, massively increases your chances of avoiding a hit. This isn’t always possible or desirable – your Rangers’ sword attacks might leave them exposed, or enemies with area-of-effect attacks might force a few people into the open – but as a general rule, it’s one to follow. The most obvious is that you should try to end every turn with your soldiers in cover. Nonetheless, most of the tactical fundamentals remain the same. Heading into combat zones with a small squad makes a bit more sense this time around, what with you being a tiny, underfunded guerrilla force rather than a global defence organisation.