Since no one seems to want to answer this question I happened to search through the community about other users not being able to use Leo. I found this solution to activate it:
Type this in your address bar: brave://flags/#brave-ai-chat
Activate Brave AI chat (Notice that this says it’s an experimental feature, even though they have said it’s ready for all users of version 1.60 on desktop, so I am not sure what can happen)
They say it’s being rolled out over the next few days from Nov. 2. - I’m not sure how long a few days are to Brave, but I’d say 7 days is more than that, and without an update saying that the feature is delayed I have to guess they either don’t care about informing us or haven’t rolled it out to everyone for some reason.
Maybe they are slowly rolling it out, and it will come to you. Keep trying - just type * at the address bar on a New Tab - it worked for me, and had my first chat with Leo!