TyroP, apologies if my post is unclear, was probably thinking faster than I can type. What I meant is that by switching the pointers off after TO I subsequently have to make a conscious effort to switch them back on in the correct way during the approach. I will then have a fresh mental picture of what is pointing to where.
If I leave them in the TO setting, there will be a day, on a rushed and stressed approach on the fourth flight of a fifth early, on which I will have programmed the whole aircraft through the FMS (MCDU) forgetting to point the pointers correctly..which might lead to mistakes.
I know it sounds a bit ott, and also on the Bus the pointers have their separate shape and color. Still, a mistake is easily made, and this is my way to prevent it. That's all. (and answering the initial question, that might be a reason for deselecting the RMI's after landing!)