Keep in mind that "gimmies" are differentiated from putts that are conceded by an opponent. In match play, an opponent can concede a short putt to you, allowing you to pick up without holing out.
However, a "gimmie" is a putt that you request be conceded, as in, "Will you give me that one?" (hence the term "gimmie"). Conceded putts in match play must be conceded by an opponent entirely on their own, without prompting.
In stroke play, neither gimmies nor conceded putts are allowed under the rules.
One of the first rules in the book - Rule 1-1 - states that the ball must be played until it is in the hole. The only exception to that is for conceded putts in match play.
No gimmies allowed under the rules.
