Shorter PreCheck lines are a nice perk of an underused program, but were not the main motivating factor for me. The biggest advantage in my view is not having to unpack and undress in the middle of the terminal - basically taking us back to pre-2001 screening techniques, with the added layer of sorting passengers with more than minimal risk to a high level of screening. If I do carry on only, then I have to deal with a laptop and liquids, plus taking off shoes, and a coat in winter. It's clumsy and annoying. I will gladly wait a bit longer in line to let other have an overall easier experience.