United Airlines New Promotion Bonus Up To 10,000 Miles (Targeted)

I opened my email this morning and found this new promotion from United Airlines in my inbox. MilePlay appears to be targeted and has several different offers depending on who is receiving. My offer was 4,200 miles if I take 1 trip by March 10, 2019 that cost more than $125.
Our friends over at Million Mile Secrets say they received several different offers:

• 6,000 bonus miles for 1 flight that costs at least $175
• 3,500 bonus miles for completing 1 flight that costs at least $175 plus complete various other tasks for 500-1,000 miles and get a bonus 5,000 miles. 
• 900 bonus miles if you fly in Economy Plus 1 time by March 10th

I checked various flights from San Diego (my home base) to see if it would be worth it to do a run to collect the miles.

• San Diego to San Francisco round trip costs $134 so that would qualify. 
• San Diego to Las Vegas round trip $154, but stops in San Francisco 
• San Diego to Los Angeles round trip $291

If you have a trip planned or need the miles to top off your account for a FREE flight, this might make sense. However, I could buy 4,000 United miles for $140 and I wouldn't have to spend 6 hours of my time flying.