OK, I'll expound a bit.
The OP is asking if Clear makes sense, given that Pre-Check exists.

Pre-Check is not always available. You are not guaranteed to get Pre-Check on every flight even if you are accepted into the program. Also, GE is currently a prerequisite for Pre-Check, since it is a trusted traveler program. I was denied GE (Yes, I'm one of the "bad" guys). I fly a lot out of SFO, and with Clear, I know that I can clear security in less than 3 minutes every time. I wouldn't have that assurance with Pre-Check.

Honestly, I think a lot of folks are down on Clear only because of the $179 annual cost. But when I consider what my time is worth, the cost is minimal. In fact, even if I was accepted for Pre-Check, I would probably still keep Clear. And I can add a family member for $50. I pay more than that (and get less) for the annual dues to a professional engineering organization that I belong to.

As an added bonus, I love the open-jawed looks and stares from the pax in the 30 minute long security line as I get escorted to the front of the line. And they do escort you, so there are never any confrontations with pax.