Oh nah, that's just us running into agonizing death, financial ruin, and obnoxiously complicated conversion practices. You know, like a glass 8oz full instead of 8oz empty.

Not important, and in fact at this point in time I wouldn't do it at all. There are some differences between how the Gulikit hall effect sticks perform vs. the standard Deck sticks in that they reach their maximum outer bounds much earlier than the Deck sticks. For example when you push a normal stick to the outside edge of the shell enclosure it's in, that will be when it reaches its maximum value. When you do it with the hall effect sticks (at least the Gulkit model which is the only variety available at the time of this post), they're reaching the maximum value well before hitting that outer edge. So while the hall effect sticks are more accurate in comparison to the normal ones, for a lot of people it makes the Gulikit sticks feel overly jumpy. People who aren't used to sticks with short throws like that are going to struggle to adapt, and having used modular gamepads in the past to lower the point that stick max is reached it felt terrible and oversensitive to me. And in the case of the Gulikit sticks it can't be fixed using hardware changes or software calibration, so buyer beware.

Honestly if my stock sticks started going bad I'd just buy the official replacement ones from iFixit and skip the hall effect ones.

The iFixit replacements also come with brand new plastic sticks already attached to the boards and are drop-in replacements with no extra work beyond unscrewing the old sticks and plopping in the new ones. Gulikit requires you removing the old plastic stock sticks and attaching them to the Gulikit boards, then an extra step of soldering a wire if you want to retain capacitative touch. So that's something to keep in mind if you're averse to soldering and care about the feature, or if your plastic sticks are also worn because you'll be stuck with them. Maybe in the future Gulikit will make a v2 with an adjustment screw for the max outer threshold and offer an option for pre-soldered sticks. That would make me a lot more interested, but for now I'm staying away.

Personally I've played over 600 hours on my Deck in the last year and the sticks still feel just as great as when I bought them, and I do play plenty of twitchy FPSs and stuff like Hades where the sticks are seeing a lot of heavy movement. One thing that I do right away for games that use L3 (sprinting, mantling etc) or R3 (flashlights, grenades, dodges, firemode changes, zooms you get the idea) extensively is to bind 2 of my back buttons to those instead so I'm not putting constant downward pressure on the sticks, which helps with reducing wear over time and feels way better in actual gameplay because you don't risk knocking either stick's aim out of whack trying to press on them.

Edit: big edit to include even more detail on this topic.