I just wanted to come here to say exactly this.
I currently use SnagIt cause it has this functionally. I have a hotkey to go straight into drawing a region on screen to either screen record/screenshot.
I want to use bandicam cause it can record at 60fps and it has everything I want except the hotkey to go straight into drawing a region on the screen. Right now you have to open up the window, click the dropdown box, and select "Select a recording area".
The hotkey to "show/hide retangle" is okay but not good enough. When you show the rectangle, you can't close with the X button on the window, and the drawing tools don't show up when you click it.
Hope this gets added soon, and the app would be perfect, thank you!