i remember, you can use prefix searches @ddg or similar ... just redoing a query on different engins was bothersome, since you needed to jump back to the beginning or click on the icons. in the search bar, i can just ctrl+k to focus the search area again and use ctrl+arrowup/down to toggle the target engines quickly.

edit/correction: my mistake ... the arrow toggle also seems to work in the url bar. Re-Checked in a new profile, since i normally dont have it enabled. So i guess you can ignore that point on my list. Sorry.

But i guess you can still more easily change to another search engine and have it set for as long as you want. since the search area remembers/keeps you selection ... i dont think the url bar remembers your last used search engine and always jumps back to the default, if you dont explicetly change it again.