Pushing when belting

A lot of pros look like they're pushing really hard when they're belting and people generally perceive belting as something you put all your energy into. Do you have to push to belt? I know a lot of pros have bad technique and belt badly but how do you know if someone is belting with good technique? It seems like even people with good technique (like the young singer guy advertising this program) seem like they're pushing or maybe they're doing something different, I dont really get it? Finally, the chorus of Thinking Out Loud by Ed Sheeran particularly "take me into your loving arms" sounds like someone belting with bad technique and pushing a lot isn't it? If it is, it sounds good so can we still do it sometimes (I noticed he doesn't sing it that way live probably to protect his voice) or can you get a sound just as good with good technique?

Also is it ok to lose your voice when you do things like belting in shows or is losing your voice always bad?

Belting is very much a "tightrope"/"highwire" act. The goal is to use mixed voice and lean into that "yell" sound without falling all the way into a yell. If it sounds like un uncontrolled yell, it's probably not healthy. But you'd have to ask the singer how they feel! We're all built differently, and some people seem to have no problem belting in more of that "yell" sound without problems. Some singers have wider mouths, which allows them to bring in more of that "yell" quality than others. And some pros will use a little more yell at times, but they know how to modify their vowels to get back into a slightly lighter mix.

The questions to ask yourself are (1) Am I control?, (2) Am I feeling that my body is supporting the sound, or that my throat is squeezing/pushing/locking up to make this sound? and (3) How do I feel during and after singing? 

Losing your voice is always unhealthy! Belting is certainly higher pressure and more fatiguing, but losing your voice is a big red flag.