Isn't it kinda their decision? If they think it's worth it, great! Why do we have to make everything exclusive?

It was worth it. SE needs to build the userbase on Xbox One. They can't magically expect PS4 sales on Xbox One. They need to make sure that Xbox sees the same games that PS4 does. Otherwise you're always going to see spotty sales.

Of course it was worth it. Today the porting cost are so ridicously small, even smaller games are released on PS4/X1/PC combo and propably Switch will take some love ( Tegra chip ).

Good example is Gears of War 4 X1/PC - they have make a test in December with cross-play and the results are clear - 91% of participants were X1 owners, rest 9% were PC owners.
10 to 1 and MS still want to release their games on PC.

http://www.eurogamer.pl/articles/2017-01-29-gears-of-war-4-z-opcja-wspolnej-rozgrywki-na-pc-i-xbox-one

That's a bad example though. For a 3rd party developer like SE it's all about sales and nothing more. So their only benefit is additional sales that hopefully make up for the porting and support costs.

MS realeasing on Windows is something completely different. It's not about recouping development costs, it's about popularizing their platform. I doubt the amount of sales on PC is very high on the priority list for MS while for 3rd party developers it's the only thing that counts.

I think totally the opposite. But well, one can guess.

Is this exlusivity begging? BTW, I bet the game will be ported to PC as well, presumably in 2018.

Then why not release it on PS4 if it's only about sales revenue?

Because PS4 is Sony's platform and PC ain't.

Sure, unless they can squeeze some money or some kind of deal out of Sony there's no reason to ditch Xbox. The sales they did get no doubt covered the costs of porting.

So it's about supporting the platform after all.