Yes and no.
Yes, because it could detect forms of attack (especially via the Cloud) and no, because Kaspersky already has very good Web protection on its antivirus.
Personally, I don't use the extension.
Does the extension encrypt data entered on websites? I have it enabled on my family's systems solely for this reason. Other features in Kaspersky, which the extension supports, I don't use and have disabled. I asked
@harlan4096 if the extension encrypts data input on websites (without using the on-screen keyboard) in a thread. He was unsure, but I kept the extension enabled because of the protection details mentioned in the help files.
"
Secure data input on websites. The extension connects the app and the browser for transferring data entered from the on-screen and
regular keyboards. The Secure Data Input feature
only works if the Kaspersky Protection extension is enabled."
I talked with
@harlan4096 about the extension's topic.
Need Advice - Kaspersky Standard and Device Security in Win 11