kuokkamies: Correct answer leaves black locally with 4 points in sente. Since white has to play M5. But there are several lines marked wrong which leave 4 points in gote, but pointwise same result. Now in this kind of tsumego where you are left with sente/gote is irrelevant because board doesnt exist outside this problem. But if you want to improve sure it matters.
posetcay: 4 points in sente is always better than 4 points in gote when it comes to tsumegos unless specified otherwise.
irnbru: The sequence M15K16 is given as a failed sequence, yet B can then play M19 and end up +4 in gote, which is as good as several of the winning lines, and also leaves a big ko threat, so why isn't it accepted?
(e.g. J16H16K16M19M15L19K19 is considered correct, but is not better than the above.)
Also isn't TheStudent's comment correct?
posetcay: Solution tree has been revised to only accept the best solutions.
TheStudent: It seems to me that only the sequence J16H16K16M19L19 should be correct: black has already +4 points locally, and possibility of an extra point depending who plays M15 first.
In the other "solutions", there is no possibility for an extra 5th point.
Correct answer leaves black locally with 4 points in sente. Since white has to play M5. But there are several lines marked wrong which leave 4 points in gote, but pointwise same result. Now in this kind of tsumego where you are left with sente/gote is irrelevant because board doesnt exist outside this problem. But if you want to improve sure it matters.