As of update 280.130, arthros can now apparently damage stone, metal, and tek structures with their bite - Assumedly due to their acidic blood. This means that, in theory, several could be used as a sort of sapper unit to aid in raiding or destroying an enemy tribe's base. This same update makes them more susceptible to ranged attacks and explosives, though, so it is recommended to only deploy them once any turrets or defenders have been destroyed or incapacitated.
Not exactly the best combat mount, slow, stamina isn't the best, a little squishy. But a few high levels of these on base defence are pretty good. Put a few in the inner parts of your base (along with the spiders to slow them down) and the will have your enemies armour being melted in seconds!