It's not the end of the world, but it's the end of wired headphones. The dongle is a pain. Phonemakers know this, and that's why each removed the jack, to sell their new wireless earbuds. Even Samsung did this after criticizing Apple for it.
And most people who say "just use the dongle" are not using the dongle.
You got me there, I use wireless headphones. That being said, why is the dongle such a hassle? If your headphone has a detachable plug, you can easily buy a new cable with a USB-c DAC built into it.
Mainly it's an extra thing to carry around, and it probably won't be there when you need it. I tried buying 3 Lightning dongles and leaving them on all my aux cords, problem is they don't work with anything else (Mac, Windows, Android, or even older iPhones like the 6S), so you will disconnect them every time and possibly lose them that way. My wife accidentally banished all of mine into our car's seats. Then they also became incompatible with newer USB-C iPhones.
It's also less reliable than the builtin port, kinda like HDMI dongles but not as bad. My earbuds' inline mic wasn't working with them, idk why but it was fine using the jack. Sometimes my phone didn't realize headphones were plugged into the dongle and it kept using its internal speakers. Irritating when you can't rely on basic functionality like that.
Lastly, leaving the dongle plugged in can wear out the port as others have said, and you also won't be able to charge at the same time. Particularly an issue in cars; I even tried wireless charging and found that my phone overheated if it was also running nav.
With all those caveats added, the dongled jack is far more hassle than Bluetooth, and it's not because BT is particularly good. iPhones had both for several years, and BT headphones never really took off until the built-in jack was removed.
And most people who say "just use the dongle" are not using the dongle.