Cause empty space is easier to render

I'm actually composing a song about this exact phenomenon right now! I'm still extremely fond of it.

Good-looking water was what people were focusing tech on. Look at Wave Race 64. I still don't think Mario Sunshine's water has been topped.

Frutiger Aero era. Plus the evolving tech at the time made devs want to show off in-game water.

Wind Waker

Water was often used as a graphical yardstick in that era.

People like tropical beaches.

A tropical beach aesthetic killed my parents.

reminds me Mario Kart on Nintendo 64 had Koopa Troopa Beach, despite irl go karts would get totally stuck on sand, they really wanted that clear water beach look

Did they? More than any other time? I feel like they're kind of universal across all time periods, just like volcano or snow areas. Even in this picture FFX only had Besaid Island, which was a relatively small area near the start of the game (but not AT the start). It's significant to Yuna's story but I wouldn't say the game has a "tropical beach aesthetic." I'd put Tommy Vercetti there before Tidus.

Water is still hard to get right. GTV VI might do something crazy, but I think the best bet for Water is unreal 5.

Because it evoked a feeling of fun, especially when you are looking at the back of a box. Video games then all had to be hard copy media and tropical settings made for excellent marketing.