That changes from company to company I guess. The 737 has 2 cargo doors. In my company we have each hold divided into two. So the FWD cargo door gives you access to holds 1 and 2 and the AFT cargo door gives you access to holds 3 and 4 (bulk). Each hold is partitioned with a net.
In my company we’ll fill up HOLD 2 first and then HOLD 1 if required and HOLD 3. In HOLD 3 they usually put things like electric wheelchairs or company cargo equipment (Spare wheels and what not), Things that are loaded and unloaded separately and maybe have specific loading compatibilities (Dangerous goods). This way of loading works out very nicely in the -800. In the MAX that sometimes results in a CG that is too FWD and out of limits so instead of loading 1 and 2 first in the MAX they tend to send some bags to HOLD 3 so that we don’t need to move passengers before takeoff.
The main benefit of loading as much as possible in HOLD2 and 1 (FWD) is basically a shorter turnaround time. If the loaders only need to open one cargo door and use just one loading rig then they need less time to load the airplane. Some companies value that.
As soon as we’re given the final loading figures we’ll put them in the OPT (Onboard Performance Tool. Boeing’s performance app for the EFB). If the resulting CG is within limits the airplane will fly :). If if isn’t then things and or passengers will be moved around until it is.