Actually, that's true...

Sufficient for engineers? Of course it is. Otherwise Calculus wouldn't dictate a minimum of 3 decimal places of accuracy. In Calculus, number precision is practically a law. Also, since Calculus was invented to explain Physics (or so the rumor goes), Physics too has this same requirement. However, with computers of today, that 3-digit precision is actually more precise because we can have up to 15(?) digits of precision with a double-precision floating point value. This means rounding errors aren't as influential as they were when 3 digits were the best that could be done.

Of course, 3-digit precision is still pretty darn good for a tool that is used merely to estimate!