For projects where international collaboration is required, sure, agree a standard up-front, and it might as well be SI. Likewise for scientific and engineering applications, everyone is a professional and can agree to use SI. But for day to day life?
Isn't that the point? Isn't it impractical to have different set of units for day-to-day life and for everything scientific, technical, or international? It certainly feels like over time our daily life is getting more technical, and more international.