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.