I would not recommend intro. Yeah I know it can look cool and some of you may think how they are necessary and all of that stuff.
I work in marketing and I'm analytics freak. Videos without an intro have much better average percentage watched and all of those statistics that Youtube reward with promoting your videos.
Best way to blow up on Youtube is by having high click through rate and watch time/apw. Intros without any purpose are not making any sense!
EXPECIALLY if you are entertainment based channel! If you're something like Derral Eves kind of channel I think few seconds long intro will not hurt you.
But something that alot of small channels do wrong is they talk and talk and talk in the beginning and they lose big percentage of viewers because of that. You know what is really funny? They do stuff like that all the time, in literally every video.
No people don't want to listen your talk about subscribing and hitting bell notification, giving a big thumbs up and all of those things that many youtubers are saying. You lose viewers because of that and it will hurt your channel.
SHORT ANSWER : Just start with a freaking video without rambling to much!
The funny thing is that it seems my newest video is showing exactly this. I did start with a hook, line and sinker (maybe a bad one?) and then a short (2 seconds) intro. My views are higher than I have ever seen in this timeframe (217 in 36 hours approx) but the watchtime percentage is awful (6,6%) while most of my videos are around 25%.
The only thing I am not sure about right now, is whether the low watchtime is because of TikTok. I just uploaded a couple of tiktoks on there and maybe the people who just discovered me watched my newest upload and then realized it was not their level of biology education and left...
I am going to keep my eye on it. Will revert back to my old ways, with just immediately starting my video if it stays like this. It was fun designing an intro, though.