> Possibly it's useless, but there's a bunch of stuff people thought would be useless, and they've given us micro-processors, SatNav, cryptography, error-correc

> Possibly it's useless, but there's a bunch of stuff people thought would be useless, and they've given us micro-processors, SatNav, cryptography, error-correcting codes, and a million other things. You're missing part of the argument, which has to do with the nature of the kinds of structures that mathematicians find interesting. Otherwise you can use this reasoning to justify anything at all.