But how would you convince someone to buy Steem Power?

• You get the power to curate content
• You get the power to reward authors
• You may get your investment back in 2 years, IF people are still willing to invest in SP at that time and the price doesn't drop significantly, even though by then the total volume of tokens will be a lot higher

The first two are noble arguments, but in my experience people are not too keen on donating to content creators (eg. patreon, flattr, etc) or free services (eg. wikipedia, free software).
And although I'm no expert in finances, the third one just doesn't sound very convincing to me.

But most likely I'm already biased in formulating these points, so how would you describe the value proposition of investing in SP?