What happens here? 😅

Sometimes the casinos set the wrong settings.

I have seen it happened quite a few times on videoslots with push gaming slots.
Although it shows the bonus buys it doesn't mean you can buy them, the casino might have the £5 stake limit implemented on their side, and when you get above £5 they cancel the bet (I have tried it). 

Some providers also have a double check on their server side and if you are playing from the UK they refuse the bet (I have also tried it).

The client side of the slots are the same across regions, the only change is the settings that your browser get when you load it, so if you mock those settings before it reach the browser you can enable all the features.

As an example, this is also in a UK casino, unfortunately I can't bonus buy anymore because the £5 max stake policy 😭

@itaghai but unfortunately the buy features & auto spins on this one is doable,

Hm