Hello @Ros35,
This is a much reported calendar display issue and even though hosts have mentioned reporting it to Airbnb via the feedback feature there's no news of anything being done about it.
Airbnb says that most guests search by entering dates and then selecting from the listings that show for their dates. In this case your listing will appear in results if a guest searches with your Friday to Friday dates.
Yes it may be offputting for a guest who searches without dates and then selects your listing. They may think that it's available only for one night stays, Friday to Saturday.
Airbnb should mark such dates, which are available to stay over but not check in on, differently from blocked dates which are not available for staying or for checkin.
Steve.