I say go for it if it works for you. I can't do the "energy bars" anymore. They make me barf. Plain and simple. I choose to keep fueled with good food and can stand eating a banana or two before a longer workout. I'll take the king size Snickers when I go a mountaineering trip. Nothing like it on the summit. I also like M&M's...they don't get mushy with the hard shell and it is just chocolate on the inside if you like the plain ones.
I asked this question awhile ago and most people thought it might be a good idea except for the fact that the bar would probably melt and make quite a mess. Didn't think of that when I was brainstorming.
As long as it has carbs, your stomach tolerates it and you can carry it: eat whatever you want!
There is not need to get all fancy or complicate things about nutrition. Most people prefer gels or sports bars cuz it is a bit easier logistic-wise but others can't stomach those so they eat M&Ms, gummy bears, rasins, fig newtons, chocolate bars, etc.