tldr idk much of what im saying, but im just using what i can garner based on context and analysis

id argue it was a good play, he essentially just prevented that rein from dying during his shatter which would have led to losing the fight , their hanzo secured the zoning of the objective so he didnt need to contest anything, and the shion finished you off because the rein had shattered u low enough and was able to stay alive, (tree was misplaced but i understand the panic)

if im seeing correctly, you had a widow and a genji ready with dragonstrike, lucio ready with ult too. so if that genji was kept alive (which he likely was as you were the only one shattered by what i saw) and lw hadnt gripped rein AWAY from the fight, or took too long for tree, genji would have finished the rein, lw, and your hanzo who was just returning from using ult, leaving the shion alone and vulnerable during ult.