A quick question: what is the importance of letting a starter rest?

I'd been struggling with getting an active starter, having tried every
set of instructions I could find, including the starter doctor
instructions, without success. I went out of town for a week with my
barely living starter in the fridge, and when I got back it just
exploded into life.

There must be something to letting the starter rest. Otherwise why
would the starter doctor instructions be so clear about providing rest
periods? What is the reason for this? Why not just let the starter grow
providing another feeding every time it began running out of food?

Well maybe that wasn't as quick as I had expected

~Chris