Exactly. I really don't see any use in investing on altcoins for the long term, since most of them depreciate over time, leaving you with less than what was initially invested. Since Bitcoin was the first cryptocurrency in existence that came with the blockchain technology, as well as other sorts of features that makes it unique (like its deflationary model) l, it will keep rising in price for years to come.

That is why, if you're considering serious investments, that would be Bitcoin itself due to its scarcity which is often compared to as digital Gold. Just my opinion.