It depends what you're optimizing for. If it's for programmer time / inexpensive programmers, sure. But remember the (probably apocryphal) story of Jobs complaining that the Mac took too long to boot, costing human lifetimes worth of waiting per year. Look at all the slow web pages, how slow Word or Excel are, etc -- that's a lot of human lifetimes.

More relevant is power. The more wasted cycles the shorter your battery life. The hotter that device implanted in you becomes. The worse the cooling problem in the datacenter.

It's naive to think that "computers are fast enough".