1. I love him because he can be abused for 99 ebony blades at the Guild of the Wanderer in Tyrine, which bring 2575G a piece at Solwan's shop on Adretana's South Island. This will provide you with plenty of gold to buy the Manor in Adretana early enough to take advantage of all the people who want to come to the place as a refuge. -- Here's a spoler how to do this the easiest way:
Spoiler: show
2. I love him because he gets me a discount at the weapons shop in Tyrine on colossus bracers.
3. I love him because he gets me past the blockades on the coast.
4. I love him because he gets me past the blockade to the giant squid quest.
5. I love him because I can get a whole bunch of items from the Sariis above the sewers.
6. I love him because he is poisoned by my reeker bulb and I love that -- am I sadistic or what?
These things constitute my revenge against his traitorous behaviors later on.
So it's okay to love Louis... well, kinda in a weird kind of way...