Selling real estate with or without an agent/Makler?

Is it a good idea to use a real estate agent (or Makler) when selling? They seem to ask for 3% provision, which works out to 30'000 CHF on a 1m home. That seems like a lot of money for the work, which I take is estimating the value, taking photos, preparing the documents, talking to buyers and preparing the contract.

Or am I missing something? Do you think hiring an agent is worth it? Any positive or negative experiences you'd like to share? Genuinely curious.