It is gaining mainstream credibility– that’s already an enough reason for you to invest in cryptocurrency. I don’t really think the last point is making any sense at all. Yes there is a limited amount if Bitcoin, which is 21 million, but that doesn’t mean that it won’t be enough… Nobody invests with the intention of holding their Bitcoin forever, you will always sell to make profit sometimes or maybe for some other reasons. By the way, investment is not even meant for everyone, it’s all about choice and those who wants to be into it.