Pretty much.So, based on your experience, the final conclusion is, don't attempt to acquire traffic from Tier 2/3, and beginners should start with SOI/DOI offers, right?
I recommend SOI/DOI because you need less budget to see conversions. A general recommendation is to wait until you spend 10x payout to see if the offer/funnel converts. So, that's a big difference in testing budget between SOI/DOI and CPS offers.
Another thing with CPS is that you need to write long sales copy landing pages to show the visitors the benefits of the product vs survey style landing page with SOI/DOI.
Then, if you're not native from one of the tier 2/3 countries you plan to run offers in, there's the language barrier that adds to the complexity of building your sales funnel.
Best to keep things simple while you're learning the basics and gaining confidence with your tools (tracker, landing page set up, etc).