The advantages of OLCI VS. airport check-in are overstated, IMO. Nobody stands in line anymore if you don't have bags to check - kiosks are ubiquitous and you can get your BP. If you have to check bags, you have to stand in line anyway, so having a BP in advance does not do anything.

When seat selection is not available in advance and your only option is during check-in, then you may have a better selection of seats, though many pax are pre-assigned to a seat anyway by the airline and that leaves very few options. AF short-haul flights are handled like this.