Keiten is not important
In yonma, keiten is considered important because the tenpai payments are not far off from average hand values. It’s also possible to
get there somewhat safely with chii calls.
By comparison, keiten in sanma is harder to reach due to not having
access to chii calls, and it’s also worth less compared to sanma hand
values.
Pushing a dangerous tile to maintain tenpai is not a winning strategy in sanma. When you draw a dangerous tile in endgame, just
fold.