Many of us started out using a real hard-copy version of A Course in Miracles, probably the big blue one with gold letters form the Foundation for Inner Peace . I know my partner, Sharol, loves her book. She has marked it up extensively and used it until many of the pages started falling out. For Christmas a few years ago I had her book–it was the soft-bound soft-copy–re-bound by a book repairman. It cost $100, will be good for another 5 years or so, and made a terrific Christmas gift!
If you love reading your real book each morning and making notes, by all means, continue to do so. You may, as Sharol has, use The ACIM app for portability and for the reminders feature.
It’s not the format that’s important, but the sincerity of your practice. As the Course says, all that is required is a little willingness to grow in Spirit.