My understanding is that it helps anybody who is trying to readjust their case who is not 245i eligible- those marrying a US citizen, those who had a family member petition for them (after waiting 12 years or whatever it takes for a citizen sibling like in my case), or other family members.

Is there a way to not leave the country at all though? For Mexican folk, it may not be so hard to take a drive down south and stay there for a couple of weeks but I pretty much am without a native country lol.