How is it nonsense? There is no space for an ILS on 03 and the transport links are not good. This remains to be the case even if Biggin could handle ticketed flights.
03 would be solved with a GPS approach and they already have a plan for the transport problems, else they wouldn't have been trying to lift the planning constraint for all these years.
Other big airports manage with rubbish transport. Been to Luton recently? The single rail station is a bus ride away and has less trains per hour to London than Bromley South. East Midlands doesn't have anything. Bournemouth is desolate, as I found one night when Ryanair dumped me there at 2300 due snow, instead of Gatwick. It was a 5 mile walk to town/hotel/rail.
Biggin would too. It's not hard.