Are these fans worth buying? What do you think?

That review video isn't in English. I mean it looks like a basic ARGB PWM fan. I doubt you'll find hard numbers on airflow, etc.
Nitpick is that you linked a 12V RGB fan, he's looking at a 5V ARGB fan. Generally, I would prefer that Scythe fan over some rando Aliexpress fan though.
I don't think Scythe makes a 5v fan. So, maybe go with Arctic.
I don't think OP is looking for 5v fans. New member with 2x posts asking questions and only giving us video links seems more like trolling for video viewer count, not really looking for help / information. I won't open links to their vids I don't want to bump up their viewer counts. ;)
Cery cheap fans fr aliexpress with argb&pwm.

Seems you are only trolling for hits on your videos. Give us a link to the fan, not your video.