No. Obviously, I didn't address the
root cause of the restriction in my post- just stating that it was more onerous than a 10-item restriction because it specified the specific items restricted.
That said, the
reason for the restrictions was
gamist. It was another example of Gygaxian gatekeeping- something that was very popular in early (TSR-era) D&D, but quickly lost favor.
The two ways to use Gygaxian gatekeeping were simple-
First, you would restrict something by making it hard to qualify for. While this had some basis in verisimilitude, it had the unfortunate effect of creating the whole, "In order to be awesome, you already have to be awesome!" An example of this is the heightened ability requirements of subclasses.
Second was the drawbacks. In order to get powerful abilities, there would be concomitant drawbacks. You want to play a Paladin? Great- but you have to apply all the "strictures"- magic items restrictions, wealth restrictions, hireling restrictions, alignment restrictions, and most importantly, association restrictions. You want to play a demi-human with abilities baked in? Great, hope you're not expecting to advance all the levels (or get raised if you're an elf). And so on.
I hate to break it to you, but the Church does not, in fact, have a magic item restriction.