Whatever one's feelings towards the Chinese, it makes sense that...

Whatever one's feelings towards the Chinese, it makes sense that they would enquire about the intended use of the critcal mineral use lest it becomes available to weapons that may be used against them. Rather like an End User Certificate for weapons sales, i expect.
And while they may benefit from others IP in their mandates, if the buyers reply doesn't make technical sense in relation to the purchase, it'd wave a red flag. Many security applications often ask obvious questions and become more intrusive later. Its a simple first line veracity test.
Nevertheless, it will be further impetus for Western production of critical metals.