i certainly prefer hard copies over digital ones. it is so much safer to have it written on a paper or even better etched on a metal or even wood rather than digitally which can be stolen or damaged.

this is a valid concern but also someone has to be looking for it in that temp memory to find it.
imagine you see this written on a wall in the street:
it looks like random data and you may just pass it but in fact it is a private key and it may contain 1000 bitcoin!

so your malware, thief or whatever has to know you printed a private key, look for it in your printer's memory, dump that memory and find the private key and steal your coins.