Wait for it. 

Some brain dead numpty somewhere had thought let's mix up two really crappy themes and get a new slot.

Slingo Starburst is born

What kind of utter deadbeat thought this was a good idea.

Slingo games are just very poor quasi bonus buys in disguise and Starburst is so crap even the streamers scoff at it 

LOL it will be Starburst megaways next.

Speaking of Slingo and  what you touched on at the end of your post, the buying extra spins feature is absolutely toxic on those games, how can anyone justify that being allowed but no bonus buys?,, must be some horror stories around.

Yes, it really is. 

Slingo games are beyond dreadful and genuinely should not be allowed as they are essentially glorified bonus buys..

Starburst is just as boring a slot as you could ever imagine with no potential whatsoever. Apparently some swedish guy managed to get 200x on it  sometime in 1976

I think casinos try and push people to play starburst as it's fast spinning, with poor payouts so probably very profitable. That's probably why they're constantly giving away free spins on it, trying to suck newer inexperienced players in.

Starburst Slingo? How would that even work? The game has no bonus.