Like Muppetteer, I also use a mini ratchet for home wrenching now and it would be much lighter and more compact than a whole set of allen keys, add to the fact that you can also take torx bits and a screwdriver bit for limit screws if they don't have hex heads, at negligible extra space
The cylinder is the most compact holder that I've seen, even more so than the Wera, which is why I'm interested in it.