Well, it's always a better choice to choose nutritional sources from actual food, but supplementing with things like these can be useful in your day.
From what it says,
3g carb (probably sugar, maybe some sugar alcohols)
30g protein.
30g of protein is quite a chunk. If you're 150 lbs, this is a 1/5 of your requirement for the day, in just one bar.
Lower carb is generally a good thing, but if you're eating them post workout, it's probably best to have some carb with them. I'd suggest fruit or 2-3 glasses of milk .This would supply more protein and overall more calories, if you're trying to gain weight I'd suggest this. Although, having that much may be too much for you (maybe not since it's after a workout).
I can't see anything too terrible with this in comparison to protein bars, but remember the first line I typed.