Out here, a drain line can run a long way before it ever reaches the street, or the septic tank, and a lot can build up along the way. So if your drain keeps clogging no matter how many times it's been snaked, this is what's actually going on. The snake bores a hole through the blockage and water moves again, but the years of grease, soap, and buildup coating the walls of that long run never went anywhere.
Hydro jetting flushes the whole line. A high pressure stream of water scours the pipe walls from one end to the other, strips the buildup off, and carries it out of the system. On a long run like the ones out here, that matters. If you only clear part of it, the clog just ends up further down the line, and you're calling someone out again. The goal is a line that's cleared along its whole length, not just at the clog.
Does every backup call for it? No. Some clogs are simple, and a snake takes care of them completely. The contractor looks at your actual setup, tells you plainly what they see, and recommends what fits your property. Then you decide.