It is also prevalent on crypto exchanges as the remnants of transactions that remain in wallets and can no longer be user or transferred.
This statement makes no sense to me. Maybe am I missing something?
This statement refers to the fact we call "dust" also the change you leave on the exchanges (offchain dust) after you change your shitcoin into bitcoin. When you convert your BPA (BitcoinPizza) into BTC and you are left with 0.432 BPA and the minimum fees to transfer it is 0.5 PBA, then your change is basically lost (now some exchange offer ways to clean that thou), and then referred as "dust"
The guy who sent the dust is watching. But the remaining balance he could be watching anyway, even if he didn't send any dust to the address.
If you don't use the remaining balance with other addresses in the same transaction you are just fine imo. Any thoughts?
Exactly, this was more or less analysed in the OP message.