You can’t wear a bumbag for an uplift day, they’re enduro not downhill! Durr.
I’ve got a small camelbak I wear for uplifts, it’s not cool but I reckon it’s worth it- multitool, tube, pump- saves wasting riding time or runs. Wee bit of water in a sqeezy bottle- not essential obviously but you can get dry talking pish on an uplift bus, and if you’re on a fast turnaround uplift it turns time wasted in the car park into riding time. Feels like nothing once it’s on and a good bag doesn’t move around.
Does divide opinion though! Though less so once you help people fix their bike… (though actually, some mates become even more definite that carrying kit is a bad idea, once they know someone else has stuff they can borrow 😉 )
I do have one of those little camelbak things with a pocket and a water bottle holder, which I use for short after-work type rides but I wouldn’t use it for harder riding, it’s more noticable when riding and moves a lot more.