That person is a moron for not killing Edda. He threw away his potsherd and +1/+1.
Just because you can get upgrades on earlier floors now doesn't mean you usually will.

I still throw away dud 41-49 runs. Why settle for just a +1/+1 on the last boss when you can get a good upgrade run AND the +1/+1?

1-10 is way faster and just as likely to upgrade them as doing 41-50 again.
Way faster, yes.
Just as likely to upgrade... definitely not.