In addition to the point raised by wool_gather, why do you need a paper trail with non-anonymous voting? The votes never need to be re-counted, as far as I know. A senator would surely notice if a "yea" appeared next to her "nay" vote.
I said that before realizing the article was about literal senators voting remotely. My bad.
What physical paper trail currently exists? For a voice vote, there's no counting; for a standing vote, there's no individual identification of senators; for a roll call vote, it's centralized through the clerk anyways.
This was the first comment on the article and I responded before reading that it was about senators voting. Not everyday citizens/residents voting.