I don't think it's a flex per se, but more of a nod to where many people start off in their electronics careers. The LM555 has been used for four(?) decades to teach electronics to students.

A cheap $1 8-pin microcontroller (attiny, avr8, pic) could do the job of an LM555 without the LM555's required capacitors/resistors. But that's not as fun.