Yes, that's a good question. Why would you need to install a new glibc? Well, there are several reasons: .:: chromewebstore.google.com ::.
you are a developer and you need the new functions of the library .:: telegra.ph ::.
you wanted to compile a new program that needs the new library .:: telegra.ph ::. .:: wiki.0-24.jp ::.
you like the thrill of errors and bugs in new versions ;-) [Research Paper: HTTPS] [Academic results for Linux]