Is the Magic Mouse 2 compatible with a MacBook Pro 2017?

Not at the moment, or possibly, ever. Because the MM2 also works with other Macs the cable for the 2017 MB Pro (exceptionally) will need a USB-C to USB adapter. I've not seen an Apple explanation for this curiosity and I cannot see them complicating the sales floor with alternate cables being pre-boxed.

I cannot speak for Apple but when you think about it, many fewer people will use a mouse with a laptop when the built in track pad is so close to hand. I use them both but how many others do is debatable.

Incidentally, be aware of the possible need to disable the track pad when you use the mouse. This is because casual brushing on the track pad may cause the screen to react. Go to Systems Prefs > Accessibility > Scroll down to mouse and track pad > click on that and check the box at the bottom of the R/H panel which says 'ignore track pad when mouse is present'. Then, to go back to using the track pad again ... just turn off the mouse. Once the box is checked you can control the situation by turning the mouse on and off.