Simply writing papers does not necessarily measure learning. Objective tests do as well. And, who really knows for sure who is the actual author of these papers?
Objective tests, given on line are worthless. Objective testing, in my opinion is worthless, but worse than worthless if you cannot monitor the testing. Like I said plagiarism can be electronically checked. Of course, the students could pay someone else to write the papers, but there are so many of them, that it would be very difficult and expensive.