Though in Shen Wei's defence, his self-sacrificial moves are generally planned and calculated and (I think he'd argue) extremely necessary, whereas this is reckless, ill-thought-out and has a poor chance of getting the desired result.

Yes, this is a good point, though clearly in that moment Zhao Yunlan feels like it's worth the risk. (I feel it matters that for all the times Zhao Yunlan touches the Hallows, I can't think of a single instance - not one - where it actually gains him anything useful.)