Digital Editions vs iBooks for downloading and storage of books until loading into an ereader.

I am using a Mac Air with 10.9.5. I have Digital Editions v4 and I use a Kindle and a Nook to rad books on. Can I dump iBooks from the Mac? Digital Editions works great whether I am getting library ebooks from my neighborhood or buying ebooks online. Moving them to my ereaders is easy. iBooks freezes, hangs and crashes all the time. If I delete it would that cause any problems?