The phrase "unconventional choice" means selecting or doing something that is not typical or usual. It refers to making a decision or taking an action that goes against the common or expected way of doing things. Full definition
It might be a more unconventional choice for a holiday party, but dressed up with the right accessories it will make you the most fashionable person in the room. (layersofchic.com)
I've grown used to making unconventional choices because I knew I had to make them. (mindbodygreen.com)
The country's recent history shows it's willing to make unconventional choices, after all. (canadianbusiness.com)