Well, is safety's not a concern, then for many applications H2 is a suitable or superior alternative to He that is abundant and renewable.
More lift
More heat transport
Faster c
Only 10K higher Tb
Unless you're dealing with unsaturated carbohydrates easy win!
Heck, at work we are trying to retrofit our He system to run on H2 to get a massive performance boost (my idea) and ditch the He recycling system.
You wouldn't believe the pushback I got! Eventually we realized we couldn't hit the performance metrics without H2, but these folks were all upset about H2 heated to 800K. Cowards.