All devices are polled at regular intervals but the hub. So, if I flip a switch manually, I will see it in my app in less than a second.
Now, you may be talking about the Lutron Patent regarding instant zwave status. You can google it. It doesn’t really seem to be an issue for devices that don’t have it, which are all the less expensive ones out there. Others can chime in, but I don’t see it as a problem at all. The hub polls well enough for it to be a non issue for me.
In other news, peek at the Linear switches as they are less expensive than the Evolves and are well regarded here in the community. They have been rock solid for me. One note - if you are using the three way accessory switch, you will need to buy/borrow something like an Aeon Minimote to help with pairing. Not a hardship because the Minimote is quite useful as a remote for the system. I use mine in our bedroom to execute hello home actions.