That is true, I guess, and the government guarantees nothing but taxes ... but NOT getting a UPIN is for sure not going to reduce them. The whole purpose of the UPIN is for NICS to be more quickly differentiate YOU (the good guy) from the next fellow (the bad guy) with a similar name.
Take a look at the VAF application form, it asks you for the same information you furnish on form 4473. OK, you also have to submit fingerprints with the application. So, I suppose that IF the reason for consistent delays is because NICS has to decide every time if it's me, Chuck Manson, or him, Charles Manson, then yes, the VAF and UPIN should be a benefit. They can use the fingerprint card to rule out the ambiguity.
On the flip side, in the real world though, I have a UPIN and I still get delayed.
It is true all my delayed gun purchases were made while still a resident alien, I've not tried to buy one since being naturalized. But still, I'm firmly convinced that NICS knows me very, very well through my UPIN since I received a nice letter from them saying I'm good to go. I cannot imagine why I get delayed, I've given up trying to figure it out, I just plan for, and deal with it.
Based on my limited experience, which is all I really have to go on, I still believe a VAF/UPIN as a delay solution is right up there with a Vegas dice roll.