They did... but gels are a great way to get the carbs your body needs into your system quickly and efficiently.
Nakd bars have about 15g carbs, whilst gels have 25-30g. That's a big difference. Bars are harder to eat on the go, plus they need digesting. So you're making your body work harder and use the resources you need to run to digest food. And you don't feel the effect of the carbs as quickly (and they won't last as long).
Nakd bars are indisputably nicer than gels. Absolutely no argument there. But they are not an efficient way to fuel a marathon. And Berroca has no carbs in it, so will be useless as fuel. Handy afterwards maybe, but not during.
Added to which, you're supposed to take on 30-60g carbs an hour on a long run/race, so in a 4hr marathon that's 8 Nakd bars! Nice as they may be, no-one wants to eat 8 of them in that time (or carry them round).
Gels aren't very nice. But if you're training for/running a marathon, it's worth finding one that works for you (or equivalent chews etc). They are all much better than real food for that purpose.
If you're training for/running an ultra, then that's different...