it's like trying to convince a religious person that god doesn't exist, when they've become so engrossed in it.
Be careful there, thats trampling on peoples beliefs, remember religion is integral to much of society, England even has an official State Religion in the form of the Anglican Church.
New age beliefs, Religion etc are philosophies that people base there lives on. Some aspects can be bad but others good, we all have our philosophies to get us through life.
Ask yourself, does the new age stuff make her happy, was she happy before, if not why. We all do stuff because of preceding stuff. Whats her view on you and your bikes, did she feel left out, does she now feel fullfilled.
Think carefully, will expressing annoyance at her spending be accepted in regard to your spending.
Life requires give and take and acceptance of different ideas. Just because you dont like your partners choices do not make them wrong if it does not harm your relationship in a real and detrimental way.
I'm a divorcee and my ex was into alternative therapy and new age thinking. I however am a scientific type requiring proof. We debated the pros and cons of her beliefs and mine but they were not the cause of our divorce. I often let her practice therapies on me, it did no harm, I learned stuff if I could keep my mind open and she learned not to accept everything purely on someones say so.
Try to be open minded and relaxed, you dont have to believe but dont deride her beliefs either.
Right enough of my fence sitting, i'm getting splinters in my backside