It's not very premium though. I have just returned from a BCN-BJL-BCN trip in JK Premium class (upgraded with the comfort option).

Food was very boring paella without any meat, a dry piece of bread and some cheese splashed together with jam. On the return I asked not to receive my meal coz I felt ashamed having to return 90% of it uneaten the first time and especially after having spent 1 week in Africa.

They don't serve champagne, only cava and it's not a good cava - it's Freixenet!

I have not received any EB points and it is likely due to the fact that it books in R-class which is a non-earning on EB (and most other carriers).

The seats are standard seats with a slight increase in pitch.

The only good thing to say is that they reserve the middle seat for you. That was not a problem on this trip as me and my brother were the only ones in 10 rows of business.

Seeing as you are EBG you get all the good benefits anyways (priority check-in, boarding, extra luggage and lounge) so I would say it is not worth it, especially since €29 indicates it is intra-europa so a relatively short flight.