It's also a for-profit company and you're not the customer, as you're not paying them money.
I'd be way more worried how they're using the data they're collecting on you vs Google or MS
How it works now is that when Brave replaces an ad, they put the new ad in a popup, not in-page
The one type of in-page modification they used to do is that they would add a "tip" button to the content creator of some social networks like Twitter or reddit. That had nothing to do with "replacing ads" though.
> replaces an ad, they put the new ad in a popup
Incorrect. There is no 1:1 replacement. You as the user can define how often you want to receive notifications, and even then the notifications only come when you are switching context between any action. It won't interrupt you while you are watching a video, working on google doc spreadsheet or reading though HN.