- it is explicitly (or at least formerly) not considered a currency
- it is centralized (the company can freeze accounts if it wants, create more coins, or be sued)
- it's major use case is for inter-bank transfers. So if Bank A and Bank B was to exchange currency x for y, they will use XRP in-between. But this gives no value to the currency itself, it is just used as an intermediary. Is it conceivable that Ripple the company will not have enough XRP for these internal bank transfers and they are going to have to buy them back from the public??
So it seems that XRP has no value outside its use by the company Ripple. Is anyone actually using it for commerce or any other reason? It is not considered a store of value like bitcoin (in any case one would want something decentralized.
Your third point is probably the reason. People hear "banks use it" and they heavily invest in it, because banks are trusted these days. On the other hand: transaction times are pretty fast and fees are usually pretty low, so it is perfectly usable.