You know exactly what it means... There are times when extra power is required from other sources. This also happens with coal & nuclear power stations when demand is high. Wind isn't the only option, nor should it be, as I'm sure you already know & fully comprehend.
Wind is only ONE of the options and with reduced CO2 emisions due to renewable energy, the limited use of coal for supply in times of excess demand would not even worry most greenies at all. (economies of scale will further reduce costs, we are not there yet...)
As energy goes more to small scale distributed power generation, power line losses (which are quite large over the network) will be greatly reduced also. And then there is the EVIL of Energy Conservation ;-)
Surely it won't be blowing too strongly all over the Brittish isles very often... And power lines often fall over or are damaged in bad storms... Blackouts happen even with coal & nuke power stations... Surprise Surprise! (remember the HUGE blackouts in the US Sylvia?)
There is no reason why power can't be routed in-out via undersea cables, the UK is surprisingly close to Europe. just as we route power in from different states... Nothing new...
