Before answering this question, remember that Google markets two smart doorbells: Nest Doorbell (wired) and, more recently, Nest Doorbell (battery).
The first, Nest Doorbell (with cable) was called until recently Nest Hello, but the company decided to change its name. As its name suggests, it requires a cable connection.
O Nest Doorbell (wired) was released in 2017 and supports the 24-hour continuous video recording, and you can view the last 3 hours at no additional cost or up to 10 days with a subscription to Nest Aware Plus.
On the other hand, the Nest Doorbell (with battery) was released this month and supports battery power and, if you prefer, cable as well.
Since it also supports power cord, many thought it would allow continuous recording. However, as Google indicates on your website, The Nest Doorbell (with battery) does not support 24/7 continuous video recording, even when connected by cable.
Regardless of whether you choose wired or wireless installation, Nest Doorbell (on battery) cannot record continuous video history.
According to Google, the restriction is not arbitrary; it is thermal. Since it can potentially be in direct sunlight or in hot environments, the box may not be big enough to dissipate the heat generated.. This functionality would likely require a larger bell.
In the case of the battery powered setting, continuous video recording quickly drains the battery because the camera is always on and recording the scene, so we offer event-based recording with the Nest Doorbell (on battery).
In wired configurations, it also presents thermal challenges for a battery-powered device that will likely be in direct sunlight, requiring larger physical enclosures. That means adding continuous recording would add a bigger feel.
For this reason, Google has chosen to offer event-based detection. Users who prefer 24/7 continuous recording will need to add another Nest Cam with this functionality or use the older Nest Doorbell model (wired).