Not counting novelty balloons, MRI machines are probably the biggest "real world" use. Gotta keep those superconducting magnets superconducting and helium is just the thing. And every time an MRI machine has to be quenched (such as when some idiot leaves something metal too close to it), or decommissioned (which is surprisingly often) all the helium tends to be released because it's difficult to impossible to collect it.

Not sure if hydrogen could also be used, but in our high-oxygen atmosphere, having that much hydrogen in an enclosed space with spinning, sparking electrical motors is just asking for trouble, especially if the above release protocol has to be used. Fireballs are generally a no-no. Risking one in a hospital is plain insanity.

Most other uses are even more scientific, and helium has a few properties that nothing else has, so without it, the science that would use it either has to go the dangerous hydrogen route, make do with a heavier unreactive gas or just... stop.

Squeaky voices

I sprinkle helium 3 on my breakfast cereal every morning. Sure, it's wasteful but don't tell me how to live my life.