Instead you have to worry about new things, like not regularly backing up your files to new media since hard drive failures and bit rot are real. You may also have DRM, logins, and paywalls to overcome which are total non-issues with paperbacks.
Ultimately, it's a trade off. Assuming that you have a DRM free digital copy of something and that you're remarkably careful about keeping back ups and multi-site/format copies a digital file could easily last 100 years, just like a well cared for paperback could last a hundred years. At that point, the difference between them is how easy it will be to read the contents. For the digital copy you will need a certain type hardware and software which may or may not exist or be easy to obtain in 100 years, but you need nothing at all for the paperback.
I like books, so I think the best bet is both the physical copy and multiple digital copies in various formats. It's not as if we have to chose one or the other, so it's okay that both options come with different strengths and weaknesses.
Ultimately, it's a trade off. Assuming that you have a DRM free digital copy of something and that you're remarkably careful about keeping back ups and multi-site/format copies a digital file could easily last 100 years, just like a well cared for paperback could last a hundred years. At that point, the difference between them is how easy it will be to read the contents. For the digital copy you will need a certain type hardware and software which may or may not exist or be easy to obtain in 100 years, but you need nothing at all for the paperback.
I like books, so I think the best bet is both the physical copy and multiple digital copies in various formats. It's not as if we have to chose one or the other, so it's okay that both options come with different strengths and weaknesses.