For me its not bad investment. I know that it is centralized but its ability to be used on global payment has potential. I even using xrp for transacting my coins and tokens due to its very cheap fee on the exchange. If not dogecoin then xrp is the good one much cheaper transaction than eth and btc.
What I dont like is this coin has been controlled by monopolist and big whales. They are sometime manipulating its price and used for pump and dump.
It's cheap and quick but being an investment, you can have your say whether it is good or not. But if somebody says that they don't like it, you can accept that. And if you say that it's not a bad investment, then they should accept that too. We have our choices pertaining to the investments that we have in cryptocurrencies. We may disagree with each other's choices but as long as you know what you are investing at, you can do whatever you want.
I'm not investor so I cannot say if it is really good to hold it for a long period of time. I'm a short term trader who usually scalp with high leverage and usually ride momentum and swings in the market. All I can say right now that XRP is now good because there is now a momentum and its volatility look goods in these past days. I do not say that XRP is good for long term investment but I only saying that XRP is good for a short term or for scalping because of its unusual movements.