[gentoo-dev] Moving more hardening features to default?

I've noticed
<http://wiki.debian.org/ReleaseGoals/SecurityHardeningBuildFlags>, i.e.
Debian is starting to make more and more hardening features default, at
least for most packages.

Should we start doing that too? What are possible problems with that? It
seems like it's mostly about USE=hardened, right?

I've noticed that several binary drivers like nvidia-drivers are masked
on hardened - is it a problem with hardened-sources, or with hardened
toolchain?