I'm not a 1K, but before they nerfed the discounts severely for non-status United/Delta members, the amex plat CLEAR credit fully covered the main person + one family member with the general discount. Now the discount for general status members is a measly $10 less than general and it's a different story (although if you have a United credit card or status below 1K, CLEAR is discounted by $40, so with the Amex plat credit it's only $20/yr to have the primary and additional member). Hard to beat "free" for sure, but I'd take the $20/yr for the gamble of the one time a year it paid off. $189/yr? No way.

Usefulness varies by airport. When I was flying US Airways out of IAH back to PHL, the Terminal A gates were sometimes 5 minutes... and then randomly on Thursday afternoons sometimes the security would be 30 minutes. Flip side of the coin (same airport), United had it at their terminal too and it was absolutely worthless. At MCO (again... a long time ago, 2014 last time I was there) even the Precheck line could take 25-30 min wait, so skipping past the ID checker was a huge value.

HPN I never flew out of during the hours of operation (limited). LGA I think it was useful once? EWR it saves a couple minutes, but probably not enough for me to pay list for with my current level of travel (far reduced from its peak). DTW it saved a few minutes a couple times. I haven't been to ATL actively as a CLEAR member, but I hear with Delta also offering it to their highest elites that the CLEAR line can be absurdly long.