This is a very old idea, back in the day I used to write tunes that were picked up on the radio by altering the speed that I wrote to the memory. This has long been recognized as a way of communicating with an air gapped computer. This is why Tempest computers exist. (Google it)
Nice idea but at 100 bps it's not like you would have to worry about data leak. It would take forever to copy any sizeable amount of data and by that time you would likely be spotted since you have to be close by for that work.