Can anyone explain “Clear” to me?

You pay additional money for approximately the same checkin experience/time to skip ahead of TSA Pre-check.

I get why someone would pay for the service, but why is the service even allowed to exist?

Can I go on Shark Tank and pitch my innovative idea for “More Clear (TM)”?

I just don’t understand why this service is allowed to exist when it seemingly just adds more confusion to the airport security process.