Handlebar bags offer great storage capacity at the front of your set-up, both for drop bar and flat bar bikes. For bikepacking trips, the larger bags offer more space, although they're best suited to large and bulky items just like seat packs, as they can be harder to get in and out of quickly.
Mounting wise, it might take a bit of fiddling to get your dashboard set up just right, especially if you are using a bike computer and lights too. Bar shape will also play a role in system compatibility, although many will work across both straight and dropbar cockpits. However, you will need to consider how they work with the space between the shifters, how much drop there is on your bike from bar to front wheel and your front end cabling before deciding on capacity.
You might find a handlebar harness is a good alternative for you. This allows you to mount anything from a tent or sleeping bag to a drybag or small duffel bag in front of your bars. Again, like any front bag, you'll need to think about cockpit size, shape and braking, with disc brakes being preferable and cantilever the least compatible.