A club can agree that members should control it while still disagreeing over who counts as a member, how elections happen, and whether ten people at a meeting can speak for a hundred. Bylaws make those recurring questions explicit. They give ordinary organizational life a procedure that does not need to be reinvented every time.
Bylaws connect an organization's purpose with its roles and decision procedures. They must fit both the kind of organization being governed and the legal framework it operates within.
Small rules can decide large disputes
Consider a music society whose bylaws specify notice periods, officer terms, a quorum, and a process for amending the rules. An unpopular committee cannot legitimately avoid an election just because organizing it is inconvenient; members have a recognizable procedure to point to.
Details can also be manipulated. A meeting scheduled with inadequate notice may formally exclude nobody while practically excluding many. Complicated amendment rules can freeze outdated arrangements. Conversely, bylaws that include every minor working preference become tedious to update and invite routine noncompliance.
The useful boundary is between stable governing rules and ordinary operating choices. Keeping those layers distinct lets members know which decisions deserve a formal process and which can be left to the people doing the work.