Bikepacking - a viable alternative to racks & panniers

So before I went to Scotland, I brought this, an Alpkit Gnaro;

I underestimate the sizes as it's smaller than I thought however it was enough to shove my sleeping bag in without the cover.

I wouldn't really recommend it because the strap doesn't hold when tighten up, which mean when you add a bit of weight by strapping stuff on the yellow core, it kept loosing up way too easily to the point I end up looping some toe strap (it got some molle webbing luckily) to secure it further.

It's a shame, cause it's a cracking little budget bar bag for ultralight touring/long day on the saddle/beach etc. had it not been for the strap not being secure nor have any lockable clasps/