It may seem irrational, but it's a bit of a leap to go from blinking an LED on a breadboard with an Arduino to blinking an LED with an ATtiny3217 (or whatever)

It may seem irrational, but it's a bit of a leap to go from blinking an LED on a breadboard with an Arduino to blinking an LED with an ATtiny3217 (or whatever) soldered onto a custom PCB. I mean: Why re-implement an Arduino (and potentially do it badly) on a custom board, when one can just install a DIP socket on some protoboard and plug a relatively small widget like this in -- retaining all of the features that were useful in the beginning of the development process?