I would argue that.
Hidden power, while useful on Jolteon, isn't even necessary for the most part. Thunderbolt/Shadow ball/Signal beam may not have " BOLT BEAM COVERAGE" but it hits enough and makes use of what resistances jolteon has to its advantage.
Being the fastest useful ( because as we all know, ninjask is not useful in real battles ) Sub/Baton passer in the game can catch even good players off guard. Subing up and baton passing to something that is immune to whatever attack your opponent picked can sometimes be good game right there.
Blinding fast speed ( 130 base ) means jolteon can revenge kill a majority of pokemon, without the use of a choice scarf and can continue to wreck havoc assuming it's gotten in safely and its 110 base special attack should not be ovrer looked either as it has just enough power to score useful 1 and 2HKO's on a variety of pokemon ( Rotom, Gengar, Dusknoir, Celebi, Gyarados, Skarmory, Metagross, Suicune, Vaporeon, Tentacruel, Alakazam, Gardevoir et cetera. )
It's ability and , although overlooked, special defense allow it to be a decent counter to zapdos as well as STAB thunderbolts on physically defensive zapdos will take it down eventually.
Now while Vaporeon is good, the fact that Toxic and toxic spikes ruin its staying power makes it a much less viable choice for a lot of things as with its low defense it can't take too many hits while enduring poison, meaning Scizor who vaporeon can usually wall and kill off, will have no problem setting up and wiping vaporeon out.
While vaporeon may have its uses as a "bulky offense" with its 130 base hp and 110 base special attack, its meager 60 base def and 65 base speed mean many things can take advantage of it as well. I would go so far as even saying that Vaporeon is a Niche pokemon, filling a very specific role on teams, much like Ludicolo or Weavile.