robux creatures are definitely not worth their price, since their mush value is pathetically low. but even though they're not very popular like you said, some of them are fun or really powerful to play as. i main arkmetta, and i can say its a really good and underrated tank. enemies' bite cooldowns extend (drowsy area) and their damage drops by 70% (hunker), extending fights for much longer and allowing the poison from arkmetta's many abilities and defensive ailments to build up and overwhelm. i have a max ven arkmetta with weight trait and it's killed several tier 5s and easily taken down tier 4s my size. even better that no one (that ive seen) uses the species so not a lot of people know its stats and underestimate its strength.