I like your approach. I sent it to my 19 year-old grandson for comment. I never could get him interested in stamps. He wants to work in social media marketing so I thought his reaction would be interesting.
The good thing is that it prompted him to go to stampsmarter.com.
Here are some of his comments: (with his permission and some minor editing)
Stamps aren't really my niche in any way so you aren't going to get the best reaction from me lol
I believe the song chosen was appropriate for the video
When watching a YouTube video you don't want any borders. Mostly all viewers want to see full screen video. Granted it is hard to do with stamps.
Taking photos and setting it to where it automatically zooms in and out and twirls etc is a little old school at this point.
The video would've looked cleaner if it had an intro. I can do 3D or 2D intro's and send it to you in any format.
I went to the stampsmarter website and the website is a little out dated. I didn't check the desktop version but the mobile version of the website is "eh"
Lol yeah it's going to be hard for whoever's YouTube channel to attract an audience.
I can make an intro if your friend wants one. It won't take me to long. (he made one)
And if he's wanting to grow his YouTube channel specifically.
Needs to post more often.
Needs to make his videos look like it wasn't made in 2008
Also I would suggest making a short video (preferably made by a professional) with YouTube name and website name in the video. Posting the video on a Facebook ad and targeting people with similar interests.
(Also I could be wrong but I'm assuming there are more male stamp collectors than females so I would target male audience in the fb add too)
That website you provided is way better but doesn't have a mobile version which is fine but still.