What if you invest in yourself ? Or a business you know ? Bitcoin investments dont really exist because bitcoin is so volatile I guess.
You can count altcoins as investments too. Gambling is much better then HYIP though.
There are gambling sites with investment feature, you can invest as low as 10 mBTC. you won't profit much though if you invest low amount, the bigger amount you invest the bigger profit you'll make.
I think people have interest to play on gambling sites instead of investing on them. But your point is good do investment in gambling sites. It is just like investment and also our money will be saved.
This thread has long discussion, but i know in the end investors always say that investment is best and gamblers always say that gambling is best, and about me, i am a middle man, i like to do both.