This is a very good question that many applicants struggle with due to the timing constraints of R1. Of course the preference would be to leverage an on-campus visit to feed your essay fodder and school specific interest but this will not be held against you if this does not happen before submission. Most schools will track on-campus visits formally or informally so definitely make it part of your application strategy. Schools like Kellogg and Columbia really value these visits. HBS and Stanford less so given their super high yield, a candidate expressing interest is the least of their concerns.
So in short program's will value these visits even if they happen after submission, particularly if it occurs before a decision is made. But if you can't make it to campus it will not necessarily hurt you it just wont really help you.