Some on-screen keyboards DO protect against software keyloggers.
I disagree with the "Keylogger Note" for the On-Screen Keyboard Portable (https://portableapps.com/apps/accessibility/on-screen_keyboard_portable), which says: "While on-screen keyboards offer protection against hardware keyloggers, they do not offer protection against software keyloggers (which are far more common). They are primarily intended as an accessibility tool or for alternate means of text entry (pen-based computing, etc)."