If the paper originals don’t take up an unmanageable amount of space there are credible arguments for keeping the originals. Once stored properly (in archival containers), old paper is likely to continue to exist for generations. While digital files are great & useful for many many reasons ensuring their long-term preservation is more complicated. They may not survive as intact and accessible unless they and their storage media are monitored and preserved through an ongoing process.
Files can become unreadable, storage media can physically deteriorate, formats & software becomes unsupported, owners of cloud servers can go out of business.
For example, a file stored on a cd even just a few years ago, may no longer be readable: either the physical cd deteriorated, or some ‘bit” within the file spontaneously changed; and finding a disk reader to work with your current or future system may become impossible.
Best practices for preservation of digital files is to make more than one copy, store those copies on different kinds of media, check them once a year to make sure they’re still readable, and be prepared to copy them to newer technologies as older ones near obsolescence.
(I come to this with a background in commercial and museum photography)