Maybe you don't like the gilded cage that is Monaco, or you think it is bad value -- $1m will likely not even get you a nice studio apt in Monaco, but it will go a lot further in Dubai. If you're renting $10k or 20k a month will get you a lot more in Dubai than it will in Monaco. But you do want the tax benefits of not paying any tax.
England is great as a non dom, but there are restrictions on what you can and cannot do. Perhaps you are British and you cannot get non-dom status. Perhaps your main business lies in the UK and thus you can't avoid UK tax.
Perhaps you want geographical proximity to a certain area, i.e. (Eastern) Europe, or Africa, or India.
There are many reasons why people opt for certain jurisdictions.
Good things about Dubai: easy to travel, free trade zone, no taxes, and judiciary that meets western standards (for business, the civil law in the Emirate is medieval).
I 'm sure there are but its not clear a) if they started their businesses there and b) if dubai played an essential role other than being low-tax.
However, they are all spending their money in Dubai (property, purchases, etc), so generally a net win for the local economy.
A lot of foreign brands (i.e. supermarkets, car manufacturers, certain fashion brands) are concessions that are held by local Emirati families granted to them decades ago by the Sheikh. So those profits mostly flow back to the local Emirati population.
Dubai is also benefiting from the general tax and secrecy crack-down in all of EU and OECD countries like malta, cyprus ireland, switzerland, singapore (Dubai was until very recently non-cooperative jurisdiction) but it's not clear whether this will last forever. It will be interesting to see whether the UK will seek to lower taxes post-brexit.
That might change in the coming years / decades (as I also believe VAT is being introduced) but nevertheless a good base if you're operating internationally.