IMHO an agent has no business EVER telling a buyer that a property is cheap OR that it is a good investment. Using phrases like charming, and needs TLC etc are just opinions. Even a view is subjective.
True about the subjectives.
But an agent IS qualified to say something is a good investment if s/he brings data to back up the assertion. i.e., purchase cost is x, rent comp is y, closing costs and repairs will be z, expenses will be a, b, c, and d.