Those are the real and final interest rates.
Netbuilders is not a bank, it's a website, and even if it was we would never be able to offer higher interest rates than those that real banks are offering to you. If you add up you'll have 1.2%+ per year, no bank offers that these days.
If you're looking for the long term, then you'll have a good chance of getting your money back and even make some profit, now if you're looking for $1000 NB's to magically turn into $2000 NB's, the NB bank is really not the place for you.
If/When interest rates start to raise in the future it'll be a lot easier for you to get a profit, as we won't be changing fees whatsoever.