In the wild, the Achatina should not be your first item of prey, as it will crall into it's shell, which can lead to a number of problems. One being the fact that the shell has a very high defense, therefore you could kill yourself due to recoil before the thing even has low health. Another problem is that the Achatina is found in the Swamps and Redwood Forests, some of the more dangerous areas of the ARK, so while attacking the Achatina, other predators have the chance to sneak up on you while your trying to clame your snail supper.
Taming, on the other hand, is very useful for this species, as if set on wondering, can produce Achatina Paste (Cementing Paste produced by the Achatina) and Organic Polymer, which can last up to 3 times as long in the Achatina's inventory. While the Achatina collects the Organic Polymer in it's inventory, the Achatina drops the Achatina Paste that has a low despawn time, and serves as a replacement for it's feces.
Easy way to keep them in place, just fill their inventory with stone. Encumbered, they will not move, even on wander. Then for feeding, put cake in a tough. They will stay in place and alive! Making you resources the whole time... Up to the top for knowledge!
TIPP: Achatinas can produce organic Polymer. You can just craft a fridge with the organic Polymer and destroy it. Every time you destroy a fridge you get normal Polymer back. That means you can transform organic Polymer to normal Polymer. I found it out yesterday by myself.
When tamed, the Achatina can produce Achatina paste, an alternative to cementing paste, passively when on wandering. You could also collect it when they are moving, their paste/slime will be on the ground shaped in a similar feces ball.
Great for passive cementing paste ( achatina paste) gets up to 100 paste overtime. Stick them in a cage and set to wandering so they do not escape. Has great weight as a organic polymer storage container as they increase the spoil timer on it.