Since you are asking for competitive, not really, no. For multiple reasons:
- Jolteon has 65 base Attack versus 110 base Special Attack (so basically any move that hits specially will be almost twice as effective as its physical equivalent). Thus, Covet being a physical move (and a fairly weak one at that), it has litte use aside from as an annoyance to your opponent.
- Jolteon needs the moveslot. Depending on your set, you may need it for coverage moves like Shadow Ball or Signal Beam (straightforward attacker) or for status/boosting moves like Charge Beam, Substitute, or Baton Pass (support/Baton Passer).
- Most of all, it's very risky. Jolteon NEEDS an item to work well (usually for more power), and although you could steal what you need, it's too much of a risk, and if you end up with a useless item... R.I.P. Sparky T_T
If there were to be a set for it, I guess it could be like this?
Jolteon @ Aguav Berry / Sitrus Berry
Ability: Volt Absorb
EVs: 252 HP / 252 Spd
Jolly Nature (+Spd, - SAtk)
- Baton Pass
- Thunder Wave / Agility / Charge Beam
tl;dr: Is it a good move for Jolteon? No, not at all. Can it be super fun if you like trolling your opponent?