This is obviously speculative, but is the expectation that motion sensors using Matter will be significantly (or at least noticeably) faster than Zigbee motion sensors?
Matter itself is a layer ABOVE the transport layer. So it would be matter over Wi-Fi, matter over thread, or even matter over Zigbee.
I would not expect to see any detectable differences between Zigbee sensors and thread sensors in terms of response time, if that’s what you’re asking. They are identical at the physical level, and the layers above aren’t likely to produce noticeable differences in speed.