Some clarifications on @BurhanKhalid's answer, this is specific to Iberia regional jets and not just general Euro business:
Although it is not guaranteed in the 2x2 seating layout, you will probably get an empty seat beside you unless the flight is full.
You'll get complimentary food and drink on board. This is supposed to be plated on proper china with metal cutlery but this is no longer consistent and sometimes you just get something from the economy menu for free. (Economy passengers receive a buy-on-board service.) You should find that the service is more attentive as there is usually one crew member dedicated to the small business class cabin, but obviously this depends on the crew.
The physical seats are the same as in economy class, as is the seat pitch. Sometimes you get a full size pillow but to be honest I don't remember if this happens on the regional jets or just the larger planes.
In theory you have priority boarding before the other passengers, but I doubt it will be enforced at BLQ. You will also have access to the Marconi Business lounge at BLQ. Priority luggage delivery might be included, but it is not something to rely on.
Whether it is "worth it" is a subjective question that depends on your individual circumstances and indeed the price of the flight. Since you are curious you might as well try it and make up your own mind.