Personally, I think that one SHOULD have an intro.
A short, a fast - paced one, perhaps, but definitely should.
It just looks more professional, with time makes your name more familiar to the audience (after all, you're creating a name for yourself with your content; a brand). For me, that 3s intro shows me you're taking what you're doing seriously.
Now, if we're talking about 10s+ intros - then I'd say go without one at all.
There are a lot of topics already made explaining why is that such a bad decision, so I won't go into details.
These are only my opinions though c: