I like the little bottles, for nostalgia rather than practical reasons.
In the days before redundancy etc I was in a wreck (Hispania) and due to a failed SPG my buddies had run out of air and gone whilst I had plenty left
.
Anyway reg went tight, SPG said 80 bar or whatever and I swam between decks to the hatch on the bottle of my Fenzy ABLJ.
As final insurance, last ditch I'll keep it thanks - just in case.