Your claim is fallacious, because a floating-point value denotes a range of the real number line, whereas you're insisting that, no, it stands for its literal value: the absolutely precise rational number that lies at the center of that range.

That is no more true than my current body temperature being precisely 36 4/10 degrees Celsius because the thermometer reads 36.1.

All numbers in that range alias to the same double, yet differ wildly in their decimal digits beyond the fifteenth. That "long tail" of digits is a meaningless residue arising from the arbitrary difference between the chosen center-of-range point and the actual number it approximates.

> Printing only 15 digits is not doing programmers any favors

Note that the ISO C function printf uses 6 digits of precision under the %g conversion specifier by default. So a team of experts can find it justifiable to severly truncate precision on printing. I find that justifiable also, like this: printing is not only for constants, and trivial expressions like 0.1 + 0.2, but for the results of complex calculations, which accumulate significant rounding errors. Six digits of precision is prudent: for many complex calculations, it will avoid misleading the user with too much precision. Fifteen decimal digits will be wrong after just a few operations; there is hardly any "headroom" to absorb error.

> just makes the lie even worse

If merely neglecting to reveal some aspect of the stark truth is tantamount to lying, then you're also lying when you pull a number with 54 significant decimal figures out of a 64 bit double. Revealing some truth without an explanation can also be construed as "lying", as in "[N]one of woman born shall harm Macbeth".

I personally find it convenient that when I bang the token 0.3 into my REPL, it comes back with a tidy 0.3. I know that there are several values of double which will print as 0.3, and don't compare with exact equality except in special circumstances (like when deliberately using integral values not far from zero).