elon promoting dogecoin is not good even if it is a cryptocurrency it makes Bitcoin look bad because instead of promoting a legitimate currency like Bitcoin he choose to pick a meme coin which has now branded Bitcoin as a joke.
Elon musk sees it from a different point of view, the question is, why did elon musk choose dogecoin over bitcoin.? Of course Elon Musk can get multiple profit from Dogecoin, because as a big businessman, musk has calculated the benefits that can be obtained from dogecoin. The calculation is like this, if musk buys BTC and DOGECOIN at the same time for $1000, 1 BTC = $1000 and 1 Doge = $0.02, after that Btc and doge both experienced an increase of 10%, so for this reason musk is more interested in boosting the prestige of DOGE than BTC.