Recently, it turned out that Taproot can be used for NFTs, and it is side-effect that was never planned. For that reason, any feature that could have undesired side-effects, will take a long time to introduce. And confidential transactions is one of those features.
I really didn't expect this circus with ordinals and posting stupid rock images on Bitcoin blockchain... now they even have dex exchanges for trading this stuff, result is that 1 sat is not 1 sat anymore. 
Can you guess what would be the worst case scenario in case if confidential transactions get introduced after soft-fork in Bitcoin?
I am sure there would be much higher transaction fees, and blockchain size would increase a lot, but I am asking for other things that could happen.
I am all for using sidechains and second layer for privacy, but I would prefer if Bitcoin introduced privacy on mainnet years ago.