Do you really need the basics explained to you?
There's no need to be condescending.
If you're not good enough to play NBA but wish to be a professional basketball player you go and play at the next highest level, wherever that might be. Europe, Asia, Australia. Otherwise you go out and get a regular job.
And yet you have Aussies playing in Europe instead of the NBL, Europeans playing in China instead of Europe, Europeans playing in other European countries instead of their own.
It's a way to be seen - get your foot in the door by joining a smaller european league.
And yet there are Aussies playing in Japan, Korea and China. And plenty from all countries in English leagues two or three divisions below the Premier League, who are never going to play for a Premier League club but choose to go anyway. I highly doubt any major league is scouting the English division 3 for talent. How does that equate to trying to impress the big boys?