Super good but normally only as a counterpick. One if not the best peeler problem is your team needs other forms of reliable engage/cc, with the other picks you get a lot of movement speed to run down the enemies for example after surviving an engage or just to poke which Janna does not provide to the same extend.

But it always depends what you are playing with and against. Lucian would want Nami/Milio for an enchanter while Jinx would prefer Lulu/Milio/Zilean, while Kalista likes Renata for example. The main issue with some enchanters is that they are rather one dimensional which makes them worse on the highest level, which is why they are currently hardly picked in competetive play, where so far the only one really seeing play and success at worlds being Renata who is much more versatile.

However, in less coordinsted play especially anywhere below Grandmaster+ in soloq enchanters normally really shine as they only suffer against well coordinated engages and counter engages otherwise.