just to clear you out , bitcoin itself or any other cryptos like eth , bch , xrp , etc is only a cryptocurrency . you cannot call them an investment but rather you can use them to be able to invest on other profitable activities .
@op you can invest your bitcoin on ico's becauase ico's are the most promising investments on this current year . you can earn a big bonus and perks when you invest as early as possible , plus you can sell you shares at the end of their project to earn again a huge profit .
I really do not get the point you are trying to drive out here. As long as something increases in value over time, that is considered an investment. The only part to it is that it also serves every other benefit and advantages as well when compared to its form as a currency and that is what gives it the value in the first place. Therefore, it is not necessarily talking about you investing in ICO that matters here, since at the end of the day, you might end up investing in ICOs and still lose more than you putting into bitcoin anyway.
Now a days I do hear about sustaining income generation from master node operating. I am not recommending any one particular coin for that but just sharing we I have observed from my friends and from this forum. After POW and POS, I guess MN will be the new way of mining but need to be as much as care how we did for other types of mining.