Although arguably quite similar, i’ve found booking an Avios reward flight and opting to part pay with Cash can often be pretty good.
On a recent Club Europe flight, I was offered to pay an extra £60 to make it 8000 Avios cheaper which worked for me.
Assuming there’s Avios availability, it’s worth checking all 3 for the best deal:
Book with money, part pay with Avios
Book with money, upgrade with Avios
Book with Avios, part pay with Cash