Making Jump potions for crafting would be defacto P2W.

Thats a touch hyperbolic but consider a few factors. The crafters in the game are a lot more influential on the economy and gil acquisition in the game. This is because of 3 factors - Crafted Gear for DoW/DoM, consumables, and Glamour/Housing gear. The levels 1-50 exist to be the 'gate' which you have to progress through to start actually making money with your crafters in the least bit. If you can bypass that gate by just buying a jump pot, you are essentially saying you should have easier access to enhanced gil, item, and gear acquisition based on real world cash. People who have more expendable real world income will have an easier time making gil and clearing content. Not to say there isnt some of that already with extra retainers, but retainers are somewhat RNG based and are limited by your own character progression. Meaning, you cant send a retainer out to do things that are above the levels of your own character, regardless of whether it's DoM/W or DoL.

"But what about beast tribes!"

You still have to level through the 1-50 content, and even with beast tribes, those arent implemented until fairly mid to late into the xpac and do act as a means to start allowing some level of catch up to max level. You can pretty much see them as the devs balancing the time it takes to level a max level crafter by making it easier after the 1-50 gate. You still need the investment of time and effort though for 1-50. Jump potions would make getting max level crafting/gather to easy, start messing with the econ, and create a system where having more real world cash makes it easier for you. You want to argue botting, then there's no point for jump potions. If youre gonna cheat to 70, then why would you even spend money on a jump potion in the first place?