Yes, I read them back as a JS object in whole on login. A few things are mandatory (hp, position) but most are optional and are only checked where needed.

    if (player.hasSomeProp) {
      doStuff(player);
    }

With your suggestion I would have a table with 200 fields and would probably have to add a lot of related tables since some of the props are arrays, objects etc. I also would lose the ability to just load the player as is (player = documentFromDB).

With "no-brainer" I mean it doesn't take any effort when developing since the representation of the player object in runtime is exactly the same as it's stored in the database.