And the disadvantage is that you need to look at the code to understand the data.

Some things change infrequently enough for DB native to be the better solution.

A nice "trick" is to declare your enum column on the database as a string, and your enum in the code as a hash with string values. So you can have self-explained data saved onto the database, and all the niceties Rails gives you from the enum.

  enum object_type: { review: "review", purchase: "purchase", offer: "offer", reward: "reward" }
  # OR
  enum action: TYPES.map { |type| [type.to_sym, type.to_s] }.to_h

Nice! I've done #1, but #2 is a neat trick.