A mouse with Sanwa arcade buttons would be really funny to see.

Also known as the Genius Gila (which is handily shown in a few of the pics) which is selling for about US$65/£50 on Amazon

I just have to wonder at what point do I have the need to use those three buttons below the scroll wheel. Are those buttons used for specific functions or remappable?

They are remappable, what they all do by default though I have no idea. Looking at the GX gaming product page, the mouse does seem to have some pretty nice features (angle snapping toggleable, multiple DPI settings, X/Y dpi configurable independently). Not a huge fan of ADNS-9800 sensor based mice thus far myself though, the highly rated Anker "high precision" and it's cheaper clone/OEM TeckNet x9800 that I've used have both suffered shoddy build quality and the latter had the mouse wheel decide it only wanted to scroll when it felt like it. The CM Sentinel Advance 2 on the otherhand had a nice build, but the sensor was a tad jittery (no idea if firmware updates fixed that).