The abstraction is that each party gets one voice, without worrying too hard about who exactly is speaking for it, and the voting public represents the support for each voice.
I find parties better capture the fact that some voices are more supported than others. If I thought of all the voices in my head as people in a room together, I’m afraid I’d end up thinking the voices I most endorse are jerks pushing everyone else around.
The abstraction is that each party gets one voice, without worrying too hard about who exactly is speaking for it, and the voting public represents the support for each voice.
I find parties better capture the fact that some voices are more supported than others. If I thought of all the voices in my head as people in a room together, I’m afraid I’d end up thinking the voices I most endorse are jerks pushing everyone else around.