It's a nice to have but it's not
essential. Birmingham, Heathrow and Glasgow to name three have all closed cross runways in recent years. At LHR they just made it impossible to use by building parking stands at one end and having a long waiting time for these aircraft to be moved if anyone wanted to use it. Glasgow just felt they could do without the expense of having it as a runway and now use it as a taxiway. Only Prestwick really *
needs* a cross runway as frankly between October-April, it would simply close to traffic way too often due to hair removing cross winds.
* hint Built runway into the prevailing wind next time
At EDI I suspect the cross runway is ideally earmarked for proper off terminal parking.