A lot of the negative effects that come along with saliva seem to involve dryness, I have not allowed my lips to become dry at any point so I haven't come across any of those effects.
So for me the benefits definitely outweigh any negatives, If you can find any article that says that saliva in itself is bad for your lips, not just its drying effects, then I would probably change my mind.
Yes he's definitely a spammer.