IMO there's nothing wrong with both.

• Machine prints out paper ballot, properly inscribed with the selected vote so that there's no "ooh, but there's a smudge here that might mean a vote for X". It could also print out a 3D barcode that contains metadata such as time, place, machine, checksums, etc
• Human who voted can verify the correct box is selected etc.
• Vote slip goes into second machine where it's counted (or a box for later counts)
• Paper vote slips are maintained for recount/validation purposes