MLMs are glorified pyramid schemes, @Thurmanmurman.
They prey on those who are statistically more vulnerable (SAHMs, single mothers, those with disabilities, and others who can't take on work outside the home) with promises of making thousands a month, if you only spend £400 on this starter kit!
To make any real money on these you have to be in at the start. It only really benefits those who start the scheme.
The only real difference between a pyramid scheme (illegal) and an MLM is that the MLM tries to provide a veneer of legitimacy by selling physical products.
The problem here is that you will make very little money just selling the products. Because your business is not truly selling the products, it's selling an idea (which has no substance), relies on turning your customers into your competitors, and turns YOU into the product. All it has to do is lure you in with the promise of a shiny white Mercedes and holidays in the Bahamas.
If someone has to sell their products through an MLM rather than setting up an actual shop, it tells me that a) their products are not as wonderful as being made out, and b) that they're looking to make money off people, not products.