Look at the world around you. People are all different shapes and sizes, and it seems that being in “good shape” is no guarantee of physical health. It is certainly no guarantee of happiness, unless you are fortunate enough to be able to say that the one thing that would make you truly happy is being in better shape physically.
It would be easy to come to the conclusion, then, that your physical condition is not important, and that all that matters is being comfortable in yourself. In fact, that is true to a very large extent, and the importance of being in good physical condition is not really connected to personal happiness. But the reason that it is worth chasing is that it has major upsides.
The better condition you are in physically, the easier you will find it to do gruelling work. If you have strong abdominal muscles you will find it a lot easier to do something like moving house, for example. It will be considerably easier to lift heavy things and carry them, and you will feel less like death warmed up after a day’s work.
There is a correlation between physical condition and emotional comfort. Think how you feel when you are suffering from ‘flu or another illness which saps your strength. It is easier to deal with things when you feel physically ready for them, and working on your abs is one part of this. This is why it is worth working on your conditioning.