They worth the veggie cake. It gives 100 paste and organic polymer. Just level up their food so they won't be hungry fast.
I have 2 bee hives and 7 tree sap taps (important to make veggie cakes). I can produce more cakes than what my 2 achatina can consume at a time. Now, I never run out of paste and have a lot of veggie cakes (I needed separate refrigerator just for my cakes)
If you are considering breeding these, go slam your hand in a car door a few times. It will be much less painful. Literally one veggie cake per percent of growth....and it grows slow.. Digests roughly one point of food per second, so feed a cake about one for every 7 mins (during event boost) and it will gain one percent of growth.
If you want to tame it on a swap, but you're afraid that you will get sneak attacked by any of the 3 horseman of the swamp, just kidnap it with a preta and land it near your base, then you tame it without many troubles.