I recently received a contract by email from MZB Works for some short stories I sold to Marion Bradley years ago for the electronic rights.  Would I print out two copies, sign them, etc.?

Nah.  I converted them to PDF, signed them with my Notability app, and emailed them back.  A few days later, they were returned to me in PDF, newly countersigned by the estate's executor.  No paper exchanged hands.

The first story I sold Marion was to a SWORD AND SORCERESS anthology, and I sent her a printed manuscript.  Later, when I started selling to her magazine, I sent her manuscripts, but ended up mailing a copy of the story on 5 1/4" floppy.  These later became 3 1/2" disks.  And then they were able to accept the stories by email.  I haven't printed out an actual manuscript in years.  Now we're moving toward electronic contracts.

I'm waiting for the day when publishers and agents do money transfers electronically.