I suspect that Regent suspects that most passengers, best intentions notwithstanding, will not log on from home and fill out the survey. I know That I resemble that remark. When I get home I am busy going through my mail, making sure any non-autopay bills get paid, checking the garden, doing laundry, thinking about our next cruise, etc, etc.
Onboard the list of distractions is much shorter. I’m sure that most of my fellow passengers are much better organized and more focused than I but for at least some of us being required to do the survey onboard increases the likelihood that we actually fill it out.