In many countries the process is very messy, and even if you fulfill every tiny criteria the immigration officers might even prefer it. Way less mess and friction for everyone!

Of course there is some economics involved, especially if things go pear-shaped...

I've seen a lot of problems just vanish for others who fucked up, but where the agent was totally capable of fixing it all. But of course its way harder to get access to that sort of flexible solutions if you haven't been building a relationship from early on.

There are lots of scammers, of course, so it'd totally be on you to get it right, meaning that you choose the right one & keep checking for any eventualities as you go along!

In an ideal world maybe you'd want to never even consider things like these, but when its all changing this rapidly I'd say that for many it will be worth it at least studying these things...