Lots of young guys think big diameter wheels must be better, and well, even if they aren't they look more like what a race car has on them.
But race cars fit them for one and only one reason. So they can fit bigger diameter brakes inside them. If you're not going to do that you shouldn't go to bigger diameter wheels, because bigger diameter wheels have disadvantages for road use.
Bigger diameter wheels, even with exactly the same rolling diameter and with tyres on them, are significantly heavier. That hurts ride. Its hurts acceleration. It hurts steering feel.
And for the rolling diameter and width tyres that Clio Sports need, they're cheaper for 15" wheels than they are for larger diameter wheels.
Renault fitted 16s because car magazines rate new cars on specification, and youngs buy them on specification. They say this ones only got 15" wheels, which isn't any "improvement" on the previous model, whereas that one's got 16s or 17s, so it must be "better". But it isn't always really better. Its just specification for the sake of it. Its buying things so you can boast about what they've got, even if you're never going to use it, or it really isn't any improvement. That's the way the car industry and the computer industry and a whole lot of other industries work in a capitalist world. They have to persuade you to keep buying their "new" "better" products.
But a whole lot of people are starting to realise the latest generation of cars with huge wheels and wide tyres have terrible ride compared to previous generations of cars, and when you need new tyres they cost a fortune.