I have never used the DAI stablecoin. The DAI stablecoin runs on the Ethereum ERC-20 network, the fees will be expensive of course. That's why I never use DAI, I prefer to use BUSD or USDT which tends to cost less in every transaction.
But, I think usdt tether is also an erc20? BUSD is from the makers of binance so no doubt that the fees of this coin are cheap compare to other stable coins. I haven't tried to use dai yet but I am seeing a great demand for this coin.
Even if the fees in eth is still high, there are still lots of people that did not care but they still use ethereum products including usdt and the eth coin itself. I think all of those users are rich and they think that when someone sees them using an expensive coin, it makes them more proud to themselves to think they are too powerful (rich). Dai is decentralized but nowadays people didn't really care about it. Most people now use centralized services, from exchanges to cryptos.