>>512487954
Certain plants / vegetables readily absorb and hold certain minerals and/or can be sources of certain vitamins and/or antioxidants.
This is subverted by nutrient poor soil and engineered strains that do not have as much nutritious value.

Fiber is a meme. The benefit of plant fiber is the sustaining and proliferation of healthy gut microbiome which in turn contributes critical substances (vitamins, amino acids, even regulating neurotransmitters, etc).

https://www.youtube.com/watch?v=xqUO4P9ADI0

Ultimately you'd be best served to spend your resources on a varied primarily animal-product diet of high quality with some vegetables to target specific nutrients: like seaweed / sea kelp for iodine. You don't need fiber for any mechanical-digestive reason. Its partial fermentation in the large intestine will only be of benefit to you if you have a healthy/complimentary microbiome which, in turn, probably only exists if you're eating organic, unwashed, heirloom grown produce or heavily supplementing probiotics.