Not just anybody can become a legal translation offering legal translation service. In order to become one, you need to be qualified for it. Not only do you have to know at least two languages to be able to translate, but you also need to be familiar with legal terminology, which means that in practice you have to be almost a lawyer yourself.
I used to be a translator in the past and I know how it is to use your knowledge and expertise to help translate various documents. The job of a translator can sometimes be daunting and hard. You might sometimes start pulling your hair out trying to overcome some difficulties. This is why asking others to help you with your legal translation can be such a good idea, especially if you are unfamiliar with legal terminology.
I have to admit that I like to ask others for help especially if this is going to benefit me in some way. I would much rather pay somebody for translation various legal documents for me rather than try to do such things on my own and then suffer the consequences of my own actions. I trust that there are other people out there who know what they are doing.