I used Vortex in the past, and it was not a good experience for me. I'm assuming it's improved over the years; but it's basically a master installer for mods with a lot of bugs.

The biggest advantage of MO2 is being able to set up mod profiles that are separated from your game and each other. You can drop in/out mods for troubleshooting, adjust load orders, and toggle specific parts of a mod. For example, you can have an entirely vanilla version of Skyrim, and then launch a modded version through MO2. If something isn't working, you can toggle mods without messing up the load order or specific settings you've made. It also allows you to adjust the "overwrite" order of mods on the fly without losing the files from the original mod, which has been an absolute game changer for modding.

Install 50 mods at once and the game broke? You can temporarily disable half of them and check if the game still loads. It works now? Re-enable half of the ones you disabled and try again. Within a handful of launches, you can narrow down the issue to a specific mod. Was the issue a specific plugin that's supposed to make it compatible with another mod you don't have? You can disable that plugin and keep the whole mod.

Got everything working great, but now you want to make a new save with different mods, but want to be able to go back to that old save file? Make a new profile and load up whatever mods you want just for that save.