There are certainly people doing it. Anyone who holds Bitcoins who isn't moving them around is speculating in this sense. And even if you move Bitcoins around, if you don't move them sooner, you're speculating at least a bit.

As for whether it makes sense, that's a tricky question. There's always a risk Bitcoins could take a nose dive in value and never recover, say because they were made obsolete by a superior crypto-currency or impractical through governmental action.

In my personal opinion, it's a pretty good risk for money you can afford to lose. (Higher than average risk, but much higher than average possible rate of return.) But you may have to make some tough decisions when the price drops: Do I sell now, take a small loss but at least cut my losses? Or do I risk losing everything if the price never goes up? And if I do sell, and then price starts going up, when do I buy? What if I buy and then it nosedives

See What are some of the risks of speculating on Bitcoin value? for a discussion of some of the risks involved. It's a bit more focused on active trading than just holding, but there's a lot of overlap.

There are certainly people doing it. Anyone who holds Bitcoins who isn't moving them around is speculating in this sense. And even if you move Bitcoins around, if you don't move them sooner, you're speculating at least a bit.

As for whether it makes sense, that's a tricky question. There's always a risk Bitcoins could take a nose dive in value and never recover, say because they were made obsolete by a superior crypto-currency or impractical through governmental action.

In my personal opinion, it's a pretty good risk for money you can afford to lose. (Higher than average risk, but much higher than average possible rate of return.) But you may have to make some tough decisions when the price drops: Do I sell now, take a small loss but at least cut my losses? Or do I risk losing everything if the price never goes up? And if I do sell, and then price starts going up, when do I buy? What if I buy and then it nosedives

See What are some of the risks of speculating on Bitcoin value? for a discussion of some of the risks involved. It's a bit more focused on active trading than just holding, but there's a lot of overlap.