LineCollection: multiple ways of setting colors?

I am working with collection of lines, and when trying to set the color of each
individual lines I found that you can either use a 'color' or colors' (note the
's') argument to LineCollection() to accomplish the same, but that there's only
a set_color() method you can call. Is this intended?
Also, I found (and already used elsewhere) the set_array() method, which
complains when passed rgba values but works when passed a vector. I haven't
found much on its purpose, except for what appears under and the various examples using it. I guessed I am
a little confused.