Physical copies are almost always cheaper, especially if you buy used. You cannot currently buy used digital games, and the sales they go on are rarely lower than their physical copy counterparts.

I remember about a month after Destiny 1 launched the Rise of Iron expansion, I went to buy my brother the digital edition on Xbox 360 and it was like $100 USD, but there was a disx only used copy on ebay for $7. You can guess which copy I went with lol.