Yes, the rental car return counters are very close to the skyway security (#10), which then can be a shortcut to some gates, especially A, B, high C, and high G. If your flight departs from other DL gates, skyway security doesn't mean a (much, if at all) shorter path to your gate. IME late morning is likely to see TSA using the nude-o-scope at the skyway security station (as opposed to early morning or a time when this checkpoint is lightly staffed), but I haven't been there much recently.

PreCheck was wonderful when it first started at MSP, but now at peak times the problem is that you sometimes must wait in a long line to see whether you have PreCheck that day and then, if not, wait again for another document checker before going through the regular SkyPriority security line, which merger with a kettle line at the second document checker. The DL MSP line dragons are usually pretty good, but I suspect that a number of people are just saying they have PreCheck in order to gain access to the elite line.