It seems dangerous to encourage people to use the Bitcoin blockchain for messaging at all as even if this implementation has little traffic, future work may only encourage more messaging.

It seems if people want to use blockchain technology for messaging, they should create a new blockchain and not clutter Bitcoin's.

This chart is scary enough without throwing new use cases into the blockchain (e.g. messaging) that have nothing to do with Bitcoin transactions: https://blockchain.info/charts/blocks-size?timespan=all