I see both sides of this. The NOC decks are geared towards magic and cardistry. Being marked, definitely not for poker. So that brings up another question. A lot of decks we see are not suitable for poker playing. Not just because of marking, but art style or other. So should we have a section for "Art" decks? I don't think so. My reason for keeping it in Plethora is just that. It's a deck of cards- regardless of style and use. I'm not a magician or cardist, so I rarely go into Bonanza. If a deck of cards is posted in Bonanza, I probably wouldn't know about it. When I look for new cards I go to Plethora.
That's my 2 cent.
Ah, but while an art deck might not be well-suited for poker, it could still be used for such - it's just not the ideal design for the purpose, like using a pocketknife instead of the proper screwdriver. But for a marked deck, however, regardless of whether it's well-suited for poker, it could in theory be used to give you an advantage over the other players at the table, more like using a lock pick kit for entering a stranger's home instead of ringing the doorbell or asking for the key... That right there makes a world of difference.
Bicycle Rider Back: suited for all-purpose use, no cheats built-in - Plethora.
Stranger and Stranger Ultimate Deck: pretty to some, artsy to be sure, not very practical, but not impossible to use for cards - Plethora.
Bicycle "Ultimate Marked Deck," Rider Back design: can be used to cheat at cards, great for magic, can get you lots of money (or serious injury) at the poker table - Bonanza.
How is a marked custom deck (say, for example, Aquila standard, Phoenix "Jill Deck", etc.) different from the Bicycle UMD in this case? More to the point, how it is the same? I think they're too much the same for any marked deck to be treated as an ordinary custom deck.
Imagine if you will that not only are you not a magician or a cardist, but that you're a poker player. Let's say you were not even aware that the Aquila standard deck was marked and you decided to use it at your poker table. One of your buddies discovers the markings after you've coincidentally won a lot of money at the table - NOW what would you say? "I didn't know it was marked?" To a collector, it's no big deal - many collectors don't even open the boxes! But to a player, especially one that's unaware of the markings, it can be seriously bad.