Xi-1 wrote:
Sure, Mandy can fire and has hacked powers but Mimi can summon the items she needs instantly to her claws. We've seen her do this numerous times. Heck, the hose and water connection was all done in the space between panels... now what kind of hose could penetrate the armour on Mandy Mandroid? That's kind of... harsh.
I think that by including the Omnitrix in Mandy's collection Bleedman and BeeAre are trying to answer why Ben Tennyson and his team never appear in their series -- that is, if that is Ben's Omnitrix despite it being transformed into the green watch, and then the Ultimatrix in the 'Ben 10,000 Returns' and mainstream storyline respectively. Kenny was part of the original 'Ben 10,000' story, which changed when Ben didn't become as much of a jerk as he was going to be. So we don't know if this is the Omnitrix or a copy.
To clarify, Asmuth (created the Omnitrix and Ultimatrix) isn't the only one who can remove the Omnitrix. Ben did it sometime between the first and second series, and he also used the voice command on the green version, removed it by force from Vilgax, and then learned what button to push on the Ultimatrix from Albido (the one who turned into a white-haired Ben). Ben can take it off anytime he wants now, although he probably wouldn't want it advertised.
But I do think that Bleedman wants to say that Ben is dead by this time in the story because I doubt he'd let someone like Mandy have an Omnitrix, copy or not. On the other hand (heh), she's not using it. Maybe she finds its power too limited. Especially when she also has Mjolnir, although obviously she is not worthy of wielding it. Who knows? Azmuth might be dead as well seeing as how he's unlikely to let an Omnitrix go. Gwen and Kevin too, along with all of the Plumbers devoted to Earth's defense. Which begs the question: is Professor Paradox steering clear of all this for his own safety?
The trouble with eliminating Ben Tennyson is the multitude of alternate timelines linked to his story, as shown in the episode of Ultimate Alien with Eon. This means that unless Mandy killed the whole lot of them (and has rooms full of Omnitrixes and Ultimatrixes) she would have to face at least one more eventually.
If the story ever went that far, which it won't for Bleedman's purposes.
TL;DR
Honestly, the omnitrix is probably just there to be noticed. I highly doubt there's any sort of hidden meaning behind it being there.