Wartortle is viable in competitive.
However, only the NeverUsed tier set by Smogon. Its role is called a spinner, and it removes hazards on teams weak to it. Eg: if your team is weak to stealth rock, add wartortle and he can use rapid spin to remove the stealth rocks. You can usually switch in, rapid spin and switch out again without losing much HP thanks to its good bulk with eviolite. Recommended moveset:
Wartortle @ eviolite
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ability: Rain Dish
bold nature
248 HP / 172 Def / 88 SpD
- Scald
- Toxic
- Rapid spin
- Haze/ Ice beam