I agree with what Monica said ... it's more because most have contradicting thoughts when they think about money/abundance .. it's not to do with money in paper form being lesser in vibration .. it's that when most think about money, their vibes become sloppy.
I want this BUT ... so, the wanting and the focusing on the lack of it, or the memory or the lack of it makes it difficult to keep your vibration pure. Of course, like Monica said, if you have always had a good relationship with money, then it always feels good and that's a pure vibration.
Further, most people have abundance limitations in their thinking .. oh it's ok to earn XYZ amounts but not ABC amounts .. or it's OK to have enough money to buy food, housing etc. but not to buy the diamond bracelet or Porche ...
At some stage of *having it all* .. certain emotions and beliefs kick in, such as feeling guilty for having more than another, or feeling you don't deserve it all, or thinking your having it all limits someone else's prosperity, or that there is too much wastage .. etc. So, it's these types of beliefs that one must release in order to make peace with outrageous abundance.
So, take a moment to think about people who have $Billions .. what are YOUR thoughts (vibes) about them? This will give you an indicator of what beliefs need to be released (e.g Rich people are foolish/rich people should help the poor/Rich people waste resources etc. or do you feel some jealousy/anger? etc.)
So, that's what I feel Abraham means about outrageous abundance .. not to be restricted by limited thinking... not to put a ceiling on what you can ask for, not to have any negative vibes surrounding your desires.