Getting Lego here in Australia at a reasonable price is pretty difficult. For many years, consumers put up with massive price discrepencies because the exchange rate was so rubbish. But over recent years, the Australian dollar has been very strong, and yet we still pay a significant difference to Americans (and, to a lesser extent, Europeans). It's not uncommon for some Lego sets to be almost double the American price despite an exchange rate of maybe 1:1.1. And that's assuming you can actually find the set you are after. Melbourne is a city of more than 4 million people, but most of the retailers still have a pretty limited range. And most American online retailers (like Amazon) have contracts in place that forbid them from shipping Lego to Australia. So generally your online option (other than just buying from local retailers), is to buy from Bricklink -- where postage for sets is often massively inflated.
By contrast, I can go on to AliExpress and find all sorts of Chinese lego... it's cheap, they happily ship to Australia and shipping is usually free. Sure, some of the products are rubbish... but not all of them are. With a little bit of research, you quickly figure out which brands are good and which are rubbish. I've bought some Enlighten stuff which was very good. Almost indistinguishable from Lego, and generally very high quality. The clutch power on their bricks is a little bit erratic, so I'd be wary of buying a large (expensive) set. But I have no problem spending a few bucks on some of their smaller sets. At the very least, the sets are usually very generous with minifigs and accessories.
I've also bought Decool, Sheng Yuan and Lele minifigs. These are typically AUD$1.20 per figure (delivered) which is fraction of the price you can buy minifigs anywhere else. Absolutely awesome for building armies or filling out your legitimate Lego sets that don't have enough minifigs. They serve a market for customers like myself who are often more interested in figures than sets, and they frequently sell stuff that Lego simply don't make. The quality of the Lele stuff is pretty rubbish (and I believe this is similar with CB, IQ and Bozhi brands too), but the Decool and Sheng Yuan stuff is very, very good. Occasionally i've needed to swap out some parts because of quality control issues... but again, at a price of little more than a dollar per figure, the additional cost of a few spare parts is more than worth it.
For me, some of these bootleg companies are providing a product that Lego simply doesn't offer me. Why wouldn't I buy from them?