People voluntarily pay to smoke products that give them cancer which is probably more "actively harmful" than "largely useless". Which is to say that the value proposition is largely subjective so the OP is entirely within their right to wonder why on earth people pay for those things!

I think the better takeaway should be that other people have very different problems to you, don't always act rationally about things and waving something shiny at them is a good way to get them to spend.

Exactly. This story is excellent... truly inspiring!

It reminds me of PG's mantra: make something people want.