Helium is very hard to store since it's a noble gas and so monatomic; I think it's smaller even than H2. So storing it (and H2 for that matter) is hard.

Strangely, their material is able to do that while also passing water, H20, which is a much larger molecule. They suggest in the summary that there's more going on than just the size of the porosity. Haven' read more.

Maybe someone else will know how useful this is for He or H2 in solution.. I'd imagine they'd vaporize out.

Might also be useful for drying H2 after electrolysis