hi, as the addon is developed and provided by kaspersky you'd have to inquire with them what their plans are in terms of converting it to a webextension. so far your antivirus' extension has prohibited firefox from deploying its state of the art security design. the switch to a webextension-only environment means a huge gain in security on the web, since sandboxing of web content from your machine and sandboxing web content from different sources will be in place now: https://wiki.mozilla.org/Security/Sandbox - that will out-way any perceived security benefits of those addons! in addition, the addon will not be needed for security software to protect you from viruses and so on, as this is already covered by its core engine. firefox has also further [[How does built-in Phishing and Malware Protection work?|built-in protections]] that will block malicious content. one action that i'd recommend for further security is installing an adblocking addon like https://addons.mozilla.org/firefox/addon/ublock-origin/ to curb the impact of malvertising. with such a setup you are already properly protected and should feel secure and confident online...

Really useful and helpful thank you Philipp, it answers questions about internet security I could not find on a search of the web