I'd like to have the option.
For example on the rare occasion I need the € symbol I press Command-Control-Space, then use the trackpad to click the "Search" box, type "eur", then reach for the trackpad again to double click the € symbol and click the tiny close panel button.
This is vastly inferior to iOS where you just long press the $ symbol. A dynamic keyboard would help me discover the Option-Shift-2 keyboard shortcut, which I know exists but can never remember when it's needed.