I can write about track and field or band but i feel like video blogging has been more significant to me. Is this subject even appropriate?
If it is significant to you in some way and has helped you develop as a person, then yes, this topic works. Show how passionate you are about it and admissions will see you as someone who likes the irks and idiosyncrasies of video blogging (they like a well rounded incoming student body).
Also make sure to have good academics as well, because one EC won’t get you into a school of this caliber alone