For other OW FFP programs, it's super advantageous as there is no spending requirement

FE: When credited to BA Exec:

For Ruby: 300 TP - 20 TP per o/w - 15 o/w trips
For Sapphire: 600 TP - 20 TP per o/w - 30 o/w trips
For Emerald: 1500 TP - 20 TP per o/w - 75 o/w trips

However, still, there is a "4 BA flights per year" requirement

Also, it's a high advantage for people who don't start from the beginning but only completes his missing miles ( Tier Points ). Plus, as the FL's are closed, and the flights are super-empty there would be almost no disadvantage purchasing Basic Economy.