This summary is not the rule. The rule text controls.
Evidence that actually relates to the case can be used in court, as long as no other rule blocks it. If evidence doesn't have anything to do with the facts being decided, it can't be brought in.
This means the starting point in a trial is that relevant evidence gets in. Judges don't get to keep out evidence just because they don't like it or think it's unnecessary. But being relevant isn't the only requirement. Other rules might still stop certain evidence from being used, even if it connects to the case. For example, evidence might be relevant but still excluded because it's unfairly prejudicial, based on hearsay, or blocked by some other legal rule.
On the flip side, if evidence has nothing to do with proving or disproving something at issue in the case, the court won't allow it in at all. This keeps trials focused on the facts that actually matter, instead of getting sidetracked by information that doesn't help answer the questions the judge or jury needs to decide.
