A map can be valuable in its own right
A good reference entry supplies the vocabulary that an unfamiliar subject withholds from you. It can explain why two authors disagree, separate questions that sound alike and identify the works worth reading next. That is real intellectual work. There is no rule that an encyclopedia must always be replaced with a primary source.
The question is what you are using it for. An expert synthesis may be the right source for an account of a debate. A claim about the number of samples in one experiment calls for the experiment's report.
An example with an explicit publishing model
The Stanford Encyclopedia of Philosophy describes entries maintained by experts and substantive updates refereed before publication. It also creates fixed quarterly editions, allowing readers to cite an archived version of an entry that continues to change online. These are specific editorial commitments, not features guaranteed by the word 'encyclopedia.'
Sources: s1
Follow the question down one level
Read the entry's scope and bibliography before collecting isolated sentences. When a paragraph describes a result or historical document that matters to your question, follow its reference and compare the claim with that source. Note whether you are reading a quotation, a paraphrase or the entry author's interpretation.
Keep the edition you used. If a later reader finds different wording, an archived reference can show whether the entry changed. An encyclopedia works best when it helps you ask a sharper question and leaves a route back to the material behind the answer.
Sources: s1