The SI prefix thing stems from a joke anyway. Allow me to trot out the etymology again:

Once upon a time in the 1980s, there was created a program for reading ELectronic Mail called Elm.

Someone created a rival mail reader called Pine, which followed both the tree pun as well as the fact it was a recursive acronym: "Pine is not Elm".

Pine had an editor called the Pine Composer or Pico for short. Pico is both a typographical term as well as an SI unit. They may have been going for both. Too perfect a pun to pass up, perhaps.

Due to licensing uncertainty, someone else created a from-scratch clone of Pico called Nano, cementing the continuation of puns, but in the SI direction.

And then apparently someone else has decided to get on the bandwagon with Micro.