The UOSteam one is automatic, there are some tick boxes in the general tab to open new corpses within 2 tiles.
Then in the agents tab there is an auto loot.
Same setup, click the set container button and then select container, I just select the lootbag again. Then set item button and then click the items I want to loot, usually the same like gems, gold fertile dirt etc etc, I also add Arrows and Bolts to both Steam and the lootbag.
Steam auto opens and loots these items when you kill something, handy when you solo dungeons like I do in shame. No point spamming [grab everytime I kill a earth Ele, I just let Steam loot for me. When I am in a champ steam tries to loot but can't fast enough so I just shout [grab every now and again to clear the floor of corpses and carry on.
They don't really override or break each other, Steam is a 3rd party imitating drag and drop and [grab is a built in system on the shard.
The only issue I sometimes have if I am looting a lot with Steam is I can not move a stack of stuff to my bag of holding as I get a error I need to wait to perform another action. This is because Steam is imitating my dragging so I can not manually do it myself. But in this case I just shout [grab to clear the corpses Steam stops trying to loot so I can then drag my stack of reagents/bolts/arrows etc to my bag of holding to lighten the load and carry on.
I guess on another note if you want to be really hoarder like. You can set the Steam auto loot to your salvage bag or token bag and add all the salvageable items to be looted. Then you can earn extra tokens or recycle loot to materials. Although this will slow you down alot!
But this is a habit I have from every MMO. EVERYTHING sells. So loot everything. I am known for this and hoard masses of stuff. In every MMO I have played I loot a corpse dry, it all sells regardless how bad the item is. 1gold from selling a bad pair of gloves is 1gold more than you had before.