Proof of burn is primarily useful for seeding new currencies (see Counterparty from Bitcoin, Dogeparty from Dogecoin), forcing users to destroy value to create coins in another currency. Yeah, wouldn't want to use it for block mining!
Counterparty is down 50% in 1 year. Dogeparty no longer exists because their devs are criminals. Adam Levine (of Lets Talk Bitcoin) got suckered into promoting this debacle. But it wasn't really his fault. Dogeparty was a brilliant idea in theory, and a scam in practice. Just try connecting to their server:
https://wallet.dogeparty.io/So yeah, I'm agreeing with OP. Don't waste real coins on fake ones.
I really hope XCP takes off, but if you look at the wallet exchange trading volumes they are abysmal. Nobody is using it. Again, good idea in theory, never really took off in real life.