Most ridiculous offer yet from United

I don’t get it. You can now pay United more money so that you get an extra measly 1,000 frequent flier miles on your next trip.

Receive an extra 1,000 bonus miles on your next United roundtrip for just $20. Simply register
and pay $20, and your account will be credited with 1,000 bonus miles after your next paid,
qualifying flight on United, United Express® or TedSM.
         

Nobody needs 1,000 miles for $20 unless you just happen to be 1,000 mile short – and then you’ll be short when you are trying to use your miles to fly somewhere not when you are buying a ticket to fly!  To put it in perspective, you need 25,000 miles to fly anywhere so you’d be paying $500 for a roundtrip ticket in the US – something that currently goes for about $250.

I’ll stop ranting now and try to figure out why in the world United thinks this is a good offer. Or even a valid offer.