One of the most successful song-writers of the 1950s was Bob Merrill who couldn't read music and couldn't play piano. He had a small xylophone he called Suzie and he used to tap out his songs on it. He said that when he presented a song to a record company it was just a string of numbers, indicating which key to hit.
Eventually he learned to read music and play the piano and neither one of them made him less successful. As splootch said, learning to read music can only enhance your playing.
Hi, Tom. I saw this question and could help but tell you that we have another thing in common. I play the organ (started out on piano before organist left) at church also. Is that cool or what, my dear? I'd give ANYTHING if I could play by ear. I do also play the big doghouse (or upright) bass used mostly for bluegrass music and do play it by ear; but that's it. If I HAD to choose, I choose playing by ear. But I do think if you knew how to read music, it would just add to the gift you already have. Like if you're practicing with the choir or something like that, you can truly read the individual notes that are written by the composer which may add a different dimension to the piece. But you've got a gift I wish I had and, of course, you're using it to glorify the Lord. Of course, because that's the man you are...a faithful servant. I've wondered many times if I'm going to have to help you carry that crown of jewels you're going to be wearing when we get to heaven. :-)