Of course you don't need so many steps, especially if you just update one slot, but this guide wasn't meant for you either.
If you are referring to updating twrp to both slots then, it is not needed because twrp updates to both slots if you flash the zip. If you are referring to flashing rom to both slots, still it doesn't involve all those steps.
Moreover it is not about the guide being for me, it's about other users also. Instead of providing unnecessary steps, the goal should be to keep it simple and to the point so others can benefit from it.