@Max: Maybe you should READ people's comments before posting your own:
How about this: a teammate of mine brought up the excellent example of a chest high barbwire/razorwire fence with say a 8' drop on the other side. Are you planning to kong vault it? Dash vault perhaps? Certainly a dive roll is not a great idea...as I mentioned, I just have to find ONE example;-)
Now maybe you're assuming I'm 12' tall. I'm not. I'm 6'. So chest high for me is about 4' 8". Yes I can do a front flip over a fence this high. If you can't, then certainly don't.
Now if YOUR contention is that you can climb a barbed wire or razor wire (ouch!) 4' 8" foot fence with an 8' drop on the other side as fast as I can front flip it...well...I'll agree to disagree on that.
The original post was about practicality, and in parkour this argument tends to be focused on efficiency. Maybe you aren't concerned with efficiency so much as just getting over an object somehow. In that case, sure, climb it instead of flipping it. At that point I'd probably just walk around it though.