That is a one more disputable and philosophical question about trading.
I personally believe that money management is a must for a trader if they want to have consistent and stable profits over some long period of time. I mean that there is nothing 100% sure about the financial markets and the traders have to work with the probabilities. As we all know, probability cannot be 100% and there is always some room for the things to go completely wrong. So, even if you take the decisions whose success is 90% (which unreal though, but still...), 10 deals out of 100 will be a disaster. That is why, it is of vital importance to secure and hedge your budget from blowing up. That is where money and risk management come into play.
The very essense of such phenomena is not to let you budget go to the hell. Surely, by following the priciples of money and risk management, you profits will not be as high as if you traded each deal with your full budget, but in such a case your money is protected from the total loss and that is a necessary practice for you if you are not a gambler but a trader and if you want to earn from trading in the long run.