Less controversial cases can be represented by lawyers.
There are indeed some cases that can be won without a lawyer. However, not asking a lawyer to represent you does not mean that you don't need the guidance of a lawyer. A client owed him some money and gave him an IOU. The IOU is quite clear and comprehensive, with accurate name, ID number, date of arrears, signature, amount, etc. And he thought that with such "hard evidence", he could win the victory without asking a lawyer at all, and he succeeded immediately, but the fact was counterproductive.
Lawyers can generally play the following roles in the process of case representation: comprehensively and systematically grasp the context of the case, design a rigorous, operable and forward-looking litigation plan, investigate and collect relevant favorable evidence, draft and modify relevant legal documents on their behalf, rationally use litigation skills in the trial process, put forward rebuttal opinions against the evidence and reasons of both parties to the dispute, improvise, find and collect relevant laws and regulations, and issue detailed, reasonable, well-founded and powerful agency opinions.