Hello @hermannhuebers​,
My name is Henry and I am happy to assist with your inquiry, and appreciate you contacting LastPass Support!
Yes, the connection is still secure. The same encryption process is followed when you log in through the website without an add on. However, you will not be able to launch, autofill or auto save your passwords.
Please let me know if this worked or if further assistance is required.
Thank you,
Henry | Customer Care
thank you very much, that calms me down a lot. my question is thus answered.