It's very effective depending on exactly where you land. Punches on the chest can beat the breath out of the opponent which in the long run contributes to their exhaustion. Punches to the lower part of the belly and ribs can be very painful, even mind-numbing but it is also good in the long run; it slows down a fighters feet [for some reason that i do not know].
Body shots can also force the opponent to protect his body thus leaving their face open [Ali Raymi has built his record of 20 wins 20 ko all in 1st round 0 losses on this and on weak opponents].
The problem with bodyshots is that it leaves you open to overhand right or left [depending on which you throw].
Muhammad Ali built his career on countering bodypunchers. Ali fought with his hands down; his body movement and quick feet helped him evade punches to the head so his opponents would go after his body [which can't wiggle away as fast]. The problem is that this left his opponents open to overhand lefts and rights. Muhammad Ali's ''phantom punch'' that kayod Sonny Liston occurred in one of these exchanges.
Very effective !! In fact, it can take the cardio out of your opponent faster. If you make it your priority you can learn to punch to the liver and KO anybody. It seems like you get paralyzed when hit with a heavy punch to the liver. Punches to the face are good but you get over them quicker.. But the punches to the body you have to deal with them.. all fight long. They keep hurting and taking away the steam.
Very effective. Body-punching is referred to as an "investment". It is less spectacular than head shots, but body punches hurt the most. They can cause serious damage to the kidneys and the liver. But it's main objective is to open up your opponent's defense or bring his guard down so you can hit him in head cleanly. It's like cutting down a tree. You start chopping down the lower part of the trunk and the head will soon follow.
I like body punches for long distance boxer styles. If you've tested your opponents chin and head and he can take it there, then try body.
How effective is a body punch as a Jab straight to the belly button and a right after.