I use it because I want a sealing compound vs a harder to remove bolt compound.
You will find in the GM FSM's that they do call for blue loctite on the LIM bolts. My feel is that was the misconception of an engineer. I believe they felt the bolts were loosening up and causing the potential seepage/wicking of oil and coolant up the LIM bolt threads onto the top of the LIM.
In all the LIM jobs I've done, I have always used pipe sealant and never had a leak and no bolts have ever come loose or caused issues.
