The phrase "unnecessary frills" means things that are extra or additional and not really needed. It refers to decorations, features, or details that are unnecessary or excessive. Full definition
I knew I wanted something sleek and sexy without any unnecessary frills and poofs, so when I tried on a gorgeous silver silk dress at Cache I was instantly in love. (missirina.com)
Financial pressures force schools to make difficult decisions about how to allocate scarce resources, and field trips are increasingly seen as an unnecessary frill. (educationnext.org)
No unnecessary frills, just features that reignite your love affair with the open road. (fiatusaofannarbor.com)