Not only are they homophones for me, but I'm pin-pen merged, so they come out as /ðɪn/.
Historically, they're the same word. I think it's silly to have a distinct spelling for the comparative use because there's little or no chance of ambiguity.
"Richmond is a real scholar; Owen just learns languages because he can't bear not to know what other people are saying."--Margaret Lattimore on her two sons