Absolutely agree that being redeemed could be the good ending to a story. If that was your goal for the character. But often times these things happen through natural progression where redemption may not have been your actual goal. And you may just really like playing the character and want to see what post-redemption life could be like continuing to struggle with the sins and guilts of your past.
I could have rolled/shelved Thomas after he broke his chains. But it was 3 RL yrs still of RP after that where I have had a ton of character and story development on him and having been able to use all that to help others develop theirs. My post redemption/break-free has been just as, if not more satisfying than the slave RP I did. I wouldn't have wanted to miss it for the world.