I think the problem with immigration is that everything depends on the mood of the officer processing your application. A few years ago, 12 teachers went together, with a representative from the university's HR. Everyone had exactly the same documents, yet one was required to produce another document. No one understood why.
Apply at your local district office and ask them for a list of documents needed for the yellow house book. I received my pink card together with the house book.
Different offices have different requirements. Some are straightforward, some are so difficult to deal with.
I applied first time in 2008 and was told they were too busy. I was rejected 4 times. The last time I told them that it was an absolute must, so they called me in for four meetings and 10K baht under the table.
My friends in another district had no problems and got their cards without problems.
Mind you, our office is notorious for being difficult.
Now I use it in so many places that require ID. Everything seems to run so smoothly using the card.
If you retire here and continue using the Thai Social Security hospital that you are assigned to, the the pink card is a requirement. You can't remain in the SS system without.
They probably did check your visa when you handed over the passport for them to copy. Haven't you noticed how much time Thais spend looking at your passport?