It should be fine, in fact potentially a great way to preserve freshness. I think that like with beer, cans have a "cheapness" feel that you have to work against. A glass bottle that is resealable is more functional and seems more pure, even though I think you would actually get a fresher taste with cans.
But a BIG concern is that since live Kombucha keeps fermenting, it will puff out the cans so they don't look right. I don't think most people would buy a can that was puffed out at all.