Knowledge stored in physical form (tablets, paper, etc) can survive and be hidden for thousands of years. All one needs is sunlight to access it.
Digital information requires electricity and the right technology to read it. It can also be destroyed by a virus, EMP weapons or a cosmic electromagnetic event. If all the information in the world is digital, it can all be lost relatively easily. Imagine if all records, texts, videos, etc in the world were suddenly lost and there were no hard copies because “nobody uses them”.
There may come a time when people are so completely dependent on technology that they have no clue how to live without it. We are already seeing the beginning stages of this.
Same with video. Early tapes (from the 50’s) are unwatchable because there are so few players.
Even VHS is now almost kaput (I saw two players at Best Buy, one for $200, another for $300).
That ship has sailed. If all technology went kaput tomorrow, within a generation the world's population will drop by at least 7 billion due to disease and famine.