It remains to be seen what benefit is derived from a successful quiet title action, for the following reasons.

In a state with non-judicial foreclosure, the note documents the requirement to pay the debt, and the trust deed (or analogous document) documents the beneficiary’s right to foreclose if the debt is not paid.

The described events in Utah seem to render the trust deed invalid, and eliminate the right to non-judicial foreclosure. However, I have seen nothing that indicates the note was rendered invalid.

If the note is held by the original lender, or any legitimate successor to whom it has been transferred, or any legitimate successor to whom it may be transferred in the future, the debt may still be pursued.

Although the foreclosure option is gone, the note holder may still use available methods through the courts to collect the (now unsecured) debt. It is a lot more effort than calling up the trustee and telling them to auction the house, but for the amounts of money involved, I see no reason to expect that the note holder would not pursue it, by suing for non-payment, obtaining a judgment, and placing a lien on the house pursuant to the judgment.

There has been some speculation (evidence?) that original notes were mis-handled, and not endorsed and transmitted to subsequent buyers of the notes. If a note is located and makes its way to a legitimate holder with proper endorsements, it still documents a collectible debt, even without the associated trust deed.

If original notes were destroyed, as some have suggested, that obviously creates a serious, perhaps insurmountable obstacle to collecting the debt.