When I applied none of my work was digital. I sent in a portfolio and sketchbook with all traditional work. I’m not sure if the requirements have changed though, so be sure to check their website.
I was fortunate to get in the first time I applied. However, it was a lot of hard work to get in straight out of high school. Sometimes I think it would have been nice to have a year to improve more at drawing before coming here. A lot of people get in on their second try, so just keep at it! :)