I remember Cubans who moved to Spain, became Spanish citizens entered on the VWP overstayed the 90 days and the filed under the CAA. So they would have had status for 90 days and the nothing until they filed.
The HP programme I tend to think of as a 2 year tourist visa with benefits, free health insurance, work priveleges etc, really makes no sense and seems even Biden administration knew it was invested with Fraud.
This programme was not a law, Congress was not involved, I assume there was seen to be some political benefit.