> In modern systems, this sort of memory saving is pointless. By giving programmers a choice of number types, programmers are required to waste their time makin

> In modern systems, this sort of memory saving is pointless. By giving programmers a choice of number types, programmers are required to waste their time making choices that don’t matter. Even worse, making a bad choice can lead to a loss of accuracy or destructive bugs. This is a bad practice that is very deeply ingrained. Boundless arrogance, minimal information. If you want a decimal floating point type, use the IEEE formats, there are high quality implementations everywhere, and if you're using C++ you can probably switch without much more than a string replacement and a couple header includes. Douglas Crockford can be forgiven for having apparently no concept of computing at the limits of the machine (in terms of cache latency, memory size, and CPU throughput), but if you get comfortable with this level of ignorance and aren't famous, you will be highly replaceable. Added: Moore's law is effectively dead. This means that for a given CPU microarchitecture family and your monetary or spatial budget for memory, you have limited resources to achieve your goals. If you write an inefficient program with no regard for performance at the numerics level, your program will no longer automatically get much faster and cheaper to run, you will instead be contributing to the pile of performance debt your successors will be cursing and shedding tears over. Furthermore, with his "loss of accuracy" comment, he seems to imply that his 64 bit decimal types are even remotely large enough that common users will not lose accuracy (by which I suppose he really means precision).