I would never invest in centralised coins like Ripple, because I think such coins are killing the idea of blockchain and crypto currencies in general. Stable coins like Tether are centralised as well, so I would stay aways from such "cryptocurrencies".
XRP is really good if you just want much faster transactions you can use it instead of BTC and the transaction fee is much lower if you compare. stable coins such as tether is also a big help in the market you dont need to convert it directky to fiat if you already have tether.
XRP is good in terms of transactions but I dont really think that this will be top priority of crypto investors. If people are of the opinion that bitcoin charges are high then I think its profits are too high. If we make comparison on the basis of financial benefits, Bitcoin is a way ahead of all altcoins. As far as the stability goes, an investors profits highly rely on the volatility of his digital assets.
If you are looking for fast transaction and lower tx fee XRP is the best option .you dont need to make it as priority coin just use it as alternative to BTC for fast transactions and if you use coinbase wallet you can easily convert it back to btc again in just a second.