Ripple is not a cryptocurrency in any traditional sense, it is a centralized digital coin that is operated by a centralized company. It is completely different than Bitcoin or most altcoins. The reason that you find it at all on Coingecko and CMC is because of financial interests. It is not part of the crypto industry at all actually.
Well, XRP does use Blockchain tech. Right? By definition, that makes it a cryptocurrency. Not to mention, XRP uses makes use of asymmetric cryptography. Same as Bitcoin and the others. What makes XRP different from BTC is the way the network is structured/organized. XRP is centralized, or rather, a permissioned network under the control of a corporation.
At the time of this writing, Ripple, Inc. holds most of XRP's supply. So anything from bankruptcy or a government crackdown, could endanger holders' funds in the long run. People don't see it now because they only focused on making money. As long as XRP keeps going to the moon, nothing else matters.