> Floating point arithmetic spends three bits in the instruction encoding to support static rounding modes.

IMO this is way better than the alternative in x86 and ARM. The reason no one deals with rounding modes is because changing the mode is really slow and you always need to change it back or else everything breaks. Being able to do it in the instruction allows you to do operations with non-standard modes much more simply. For example, round-to-nearest-ties-to-odd can be incredibly useful to prevent double rounding.