Why registration date matters
Charges are paid out in the order they were registered if a property is sold or foreclosed. A first charge gets paid before a second, which is why the loan-to-value math has to account for anything already registered ahead of a new lender.
What it actually lets a lender do
With a validly registered charge, a private lender has the same basic legal tools a bank has: the right to be repaid from a sale of the property, and — if the mortgage document provides for it — the right to pursue power of sale on default.
What it doesn't do on its own
Registration alone doesn't guarantee recovery of every dollar loaned — that still depends on the property's actual value versus the total registered against it. This is exactly why loan-to-value discipline matters more than the registration step itself.