I played with it on the day they released Ruby 2.3. It's not meant for distributing code across machines and it could fail on the same machine after some updates. It's probably not worth it to shave 152 ms on an interactive command.
The fonts don't seem to matter. This thing is super cool but I disagree that it's not debilitating. `ls` on my home directory takes 0.005 real, `colorls` takes 0.554 real. Over 100x as long and it's an extremely noticeable half second.
Here's what `time ls` and `time lc` produced, in a directory with 517 files:
> ls --color=tty -l 0.01s user 0.00s system 93% cpu 0.007 total
> ~/.gem/ruby/2.4.0/bin/lc 0.14s user 0.01s system 98% cpu 0.159 total
It's definitely noticeable, especially if you use `ls` day-in, day-out. But it's nothing debilitating.