I bought some shoes to do my bit to help promote, though I had never purchased
from them before.  I have to wonder though what the ongoing btc revenue rate will be
for them after the one-shot first time response of people like me.

I guess the general question is

A merchant can save the ~3% and shed risk, but what is the incentive
for joe consumer to bother with bitcoin?

Even if they pass on some
of the savings, $89.95  becoming $89.05  would not be enough to
make me bother.  Maybe it helps a lot with micro-payments, but
do you think it will ever attain widespread, consistent use?

It seems like the big value of it are the things (avoiding taxation, inflation,  litigation, tracking)
that will cause great friction with the powers that be.