That link says daily from LCY and once a week from STN? Both from 19 June
It has been updated as it quite clearly stated earlier today '6x weekly'. Obviously in error.
Anyhow it's interesting and will make a handy connection for folk travelling from Berlin to London for a short weekend break, or vise versa for UK travellers wanting a slightly longer break. However for more flexibility people will choose Ryanair. What will be interesting will be whether they offer any routes for the winter 16/17 season. Ski routes could be a clear winner.