No it is not. You might find it simple, if you don't compare to places that are easier.
First you need to file all the paperwork. Then you wait. Once you get approvals, you can't do anything without a bank account, and opening the bank account is a lot of trouble too, because they want to triple check everything.
From zero to operational is a long way, and with lots of legal liability along the way. I have a company closed for 15 years that still counts as a liability to me when I try to do anything, like renting an apartment.
You might be right in "opening" paperwork only being kinda OK. But you certainly can't do it like the original poster, that codes for a week or two, opens a new business and move on to new projects in series. (Yeah, not every project of his is a new company, but IIRC the larger ones become new companies).
This is absolutely true for most companies, but in this specific case he could open a “MEI” type of business (individual micro-entrepreneur) on the government website and use the CNAE 8219-9/99 (“Digitator” or typist) to receive immediately a CNPJ, which would allow him to launch the site on the first day and charge customers, paying very few taxes and without a lot of bureaucracy (well, he would end up needing to deliver some papers to the city hall after that and also generate all the invoices, but this can be done days later, during the first month of CNPJ creation).
AFAIK it works only for his first company, which is fair, MEI is ok for a first company. But not for serial projects like his, with many different areas of business.
Also, sorry to say, but I would never have a MEI myself. The mixture of your personal legal entity (for US citizens, think of your social security number) being legally bound to your CNPJ (for US citizens, an LLC or other company) is another problem entirely. If your company gets audited, all your personal accounts and your IRS get audited at the same time? Hard no for me. Thank you.
It is perfectly possible to carry out multiple activities with the MEI, although the list of permitted activities is quite limited, specially for online businesses.
But the issue you mentioned indeed makes this solution a lot less interesting.
I don't get the appeal of Atlas. You end up having to deal with bureaucracy and taxes in the US in addition to your home country, and if you need any legal/financial advise you now need someone who knows about the situation in multiple countries.
Maybe it makes sense if you want to get funding from US investors, but for a small self-funded business I just don't see the appeal.
He would still need to pay taxes in Brazil, and explain why it's not international money laundering. Same if the money touches the US, will have to pay taxes there too, then transfer it to Brazil for more taxes and paperwork.
I haven't heard of Stripe Atlas. And it actually sounds like a good idea.
I'll take a deeper look, but you could have a company in Brazil that interfaces with the company you create with Atlas. In none of my comments in this thread I am trying to aviod taxes BTW. Would be great, sure, but not the objective. I am impressed by the lifestyle the original poster, it inspires me, to the point I would like to be able to do it. Taxes need to be part of the equation, but being viable and practical would be the main issue.
Closing a business is a bit of a bother, but it is mostly a question of waiting.