Physical books are great. I love them. I've got a whole bunch of books in physical form, and I like the way books feel in the hand.
That being said... physical space being a thing I'm not necessarily in possession of in great amounts, and given the easy availability of both data storage space and the lower price (especially for TTRPG volumes, which are often more than half the price), I prefer digital. Buying extra space for digital books is as easy as getting an external hard drive or a new SD card. It's really nice. Really, really nice. Even if I do need to swap to a bigger SD card on my phone to keep growing my library, because I have so many digital books that I've had to remove other apps to keep all my stuff on my phone.