I work in It and am usually an early adopter. I do read ebooks sometimes when traveling, but I don’t think I’d spend even half of what a printed rulebook costs on a digital one. Regarding FAQs and Errata, I remember Privateer Press providing these as stickers so you could update your books or have them as a sheet in the book.

Nothing keeps you from doing the same for you personally.

Regarding a broader switch to digital publications:

GW tried, and they’re failing, they had to cancel digital WD, and I yet have to encounter anyone buying one of the digital versions. Plenty of people using them for convenience, but no one buying them.

A few issues I have with digital rulebooks:

Battery life. Imagine your device dying from lack of energy mid game.
Resale, memories. You will never be able to put old rulebooks onto the shelf.
Haptics. You cannot lay out several rulebooks at the same time next to each other. (Well I know some high-end devices have split screens nowadays, but these are usually iPads or similar expensive machines, so often not an option).
Availability. What if the company seizes to exist? Your old rulebooks may disappear and just be removed by an auto update, or worse the company decides they don’t want to make old rules available any longer, and starts selling you only access and removes that with a new edition. Forcing you to switch and buy the new books?
Loan out a book to an interested friend. Just not possible with digital books

I don’t think we’ll switch to full digital in the short or mid future (I’d even doubt it long -term) in this hobby. This hobby lives from being haptic and old school.