One of the goals of a virtual conferences is to provide value for people paying money to attend. Mostly this is provided by interactive, live experiences for attendees; afterall the ultimate end product of published papers largely ends up readily available to attendees shortly after a conference anyway. However the opportunity to interact with paper authors, invited speakers and other attendees is a significant advantage of attending a live conference.
However even a virtual conference involves significant expense and this expense is paid for by attendee remitances.