Is the G-FC01: Fighter's Collection 2015 booster box worth it?

How to read these numbers

The full-set value is what all cards would cost as singles. One box won’t complete the set and the rarest cards are rare, so we focus on cards from €5. If they are worth many times the box price, the set is rich in valuable cards; if value is concentrated in a few cards (high top-5 share), opening is a lottery.

If you want a specific card, buying it as a single is almost always cheaper. A box makes sense if you enjoy opening, play limited/draft or collect sealed product.