>>64137529
First and foremost it's simply a very precious material (today the highest grade jadeite commands prices per carat similar to the best amongst diamonds from what I've understood, and it seems top grade nephrite can be worth not its weight in gold, but perhaps five times that). So it doesn't just symbolise wealth (and the power that comes with wealth), it is wealth.
The museum also mentioned that the beureucrat-gentlemen-scholars that dominated much of China's history also noted its combination of a generally quite gentle outer appearance with also being hard and tough, a mix they found appealing.
And clearly it is to have been considered to be general good juju in terms of the mystical and magical, as per the various grave goods and funerary rites mentioned above.