I don't necessarily agree with this. Perhaps it makes sense for a sub that is a "pain slut", but not for the rest. There is a difference between a play spanking and the one used for punishment. They are very effective.
Writing lines would just annoy, irritate and fester resentfulness. Nothing would be resolved.
I don't like pain, the turn on is His ability to cause it. Playful spankings are fun for exploring that. Seriously painful ones are used to break down walls beyond petty feelings, to "feel" his disappointment/displeasure, to clear the air, to perform penance.
Personally the most horrible thing that I have read here in the Library is someone suggesting using "ignoring treatment and silence" as punishment for a sub. Accepting that we are all different I still find that psychologically abusive, mean and immature; if I had wanted to deal with a pouting man child I would have married a vanilla.