If you look at some of the easyJet domestic routes like NCL/BRS and GLA/BFS, they are effectively flying now at peak times only - Monday morning, Thu/Fri/Sun night and a much reduced frequency at other times of the week. It is only on very high volume routes or those with direct competition that you will find what historically would have been considered to be a business schedule.
In effect, the easyJet aircraft is fulfilling the equivalent of the National Express bus to allow business commuters, VFR passengers, students, wedding/hen/stag parties to travel at the times they are most likely to want to. If you can make more by flying a single NCL/FAO rotation on a Thursday morning versus a NCL/BRS and a NCL/BFS roundtrip in the same time slot, then you will. Into that equation, you not only have to consider yield but the likelihood of passengers booking hold baggage and spending on board - both of which are likely to be higher on the FAO given length of flight and length of stay than the BRS + BFS rotations combined.