I partly agree with that. Although oat milk is not that strong in flavor as almond milk (at least for me), cappuccinos are very dependent on the milk used, to get the right texture, as opposed to just coffee+milk. So yeah, depending on the type of milk used, the results can go from great, to meh, to just "that doesn't feel like a cappuccino"

Personally I much perfer oat milk coffee than cow milk coffee, maybe depends on the brand? I'm using Karma brand from Switzerland's COOP.