1. People say this when their life seems just fine. They have no worries or whatsoever. When they are satisfied with what they have.
Because her parents worked for her she had everything she wanted and she thought life was just a bowl of cherries.
2. Sometimes it can be used ironically to mean totally the opposite meaning of the above explanation.
I don’t have enough money to pay the rent. My car needs repairing. My ex-husband is threatening to take my daughter. Life is just a bowl of cherries.