I’m with you: I read the link and think they are referring to BLE advertisements. The frequency of such advertisements is configurable. AIR, the advertisement interval has to be a multiple of 0.625msec. Per the spec, a random delay of 0-10msec is added in between the interval to aid in collision prevention.

I’ve mainly seen “BLE beacon” used to refer to types of devices, especially ones that primarily advertise.

There are some devices, like BLE-based remote controls, that advertise very frequently, I assume to reduce latency between a user’s action and response by the receiving device. It makes for a very noisy environment if you’re playing at home and not filtering based on MAC, etc.