Hi Omkar,
"It depends" :)
As stated: "ZAP will automatically download and install any updates to the scanner rules you have installed."
If you change that option then you will not get auto updates.
Also, it depends on what scan rules you have installed.
The stable release only contains "release" quality scan rules.
The docker packaged scans use both "release" and "beta" quality scan rules.
New scan rules always start of as "alpha" quality.
If you do not install the alpha quality scan rules then you wont have access to them or get updates to them.
You would only get then when they are promoted into one of the add-ons you have installed.
Does that make sense?
Cheers,
Simon