I’m curious too. As I understand it (and based on my observations after playing with it), it doesn’t change how often they send data to the controller, but instead changes how often the controller passes the data on. It doesn’t help the network, just the MQTT/Home Assistant side, but it can mean they flood the database less, if they’re tracking a value (like temperature). If they’re following a state (open or close) then I find they would miss the important messages and just not work well.
In my case I’ve found a few Tuya devices that seem like they have bad firmware and flood the zigbee network - human presence sensors and co/voc/climate sensors. I experimented with denouncing them, but I still ended up retiring most of those devices as they degraded my network performance and other devices couldn’t communicate very well. If it actually prevented the devices from flooding the network it would make a lot more sense to use.
I still have database filters to not record the main entities (for the mmWave presence sensors that I’m still using) and instead use a template on them to record their state as I found my database grew in size very quickly otherwise.