Two email addresses are enough: one for family and friends. One for subscriptions, ordering goods, the authorities, etc.
It is better to not trust family and friends as most of them have no clue what they do regarding security when browsing or clicking on an email attachment. And that can unintentionally put you in harm's way. Over the last 35 years I had to change my family & friends email address several times. The "serious" one is still the same.
I didn't say that they are lying. But such a company has to have an income. Where does this income come from besides their start-up capital?
I did not say that. But they will have to – at some point. Not because they are evil, but for economic reasons. Whe then start-up capital will be gone, they will have only two options: charge you for using the browser, or get more funding. Now tell me what is more likely?
I've been involved in some start-ups in the IT world, and the naiveté of such founders is sometimes astonishing. This is how this company starts:
How long will this money last? Two years? Three years?
And they are not in the EU, which means they do not need to publish any legal or tax information about their entity on their website. At least in the EU you know who you are dealing with, because a website needs to have some kind of Impressum, which is part of the
https://en.wikipedia.org/wiki/General_Data_Protection_Regulation. In the US only California has something similar, albeit weaker:
https://en.wikipedia.org/wiki/California_Consumer_Privacy_Act.
Using the Internet is a calculated risk, which requires a certain degree of caution, which in turn requires certain knowledge about the technology behind it.