It might be more cost effective to buy the digital only SKU as you'll likely still need to buy another SSD later on to compete with the crazy installs this console will likely have for all it's games. I guess it depends how many TB the original SSD that comes with the console has though.
At first glance the SKU with the disc drive seems better, but really unless you're die hard for collecting physical games, digital will likely be more cost effective assuming most PS5 owners will likely be buying an additional SSD.
With the way things are going, by next gen video game releases will likely be fully digital, no physical media. Sony and other publishers/developers will save a ton of money abolishing it. And maybe the cost of games will drop too because of it. Possibly.