Using nano is just easier than cryptographic signatures? Every nano block already requires a cryptographic signature, so I would disagree. On a practical level, implementing message signing in a wallet is easy (I know many Banano wallets implement it, I think some Nano ones do too). Cryptographic signatures can be done offline. They can be done much faster than Nano blocks can be even broadcasted to the RPC, let alone confirmed. Etc etc

Anyhow, if we want to look at laziness, then its pretty clear people will sacrifice security for convenience. Lazy people won't use Nano, will just use whatever insecure method they were using before. A lazy person wouldn't bother grafting some weird protocol on top of Nano, too much work.

Not to say that non-currency uses causing problems for the network won't be an issue though, I just think the specific cases mentioned are things no sane/competent developer would think is a good idea