Laggy comes from some unknown reasons related with your computer's environment.
Can you try to install/move game into other directory other than default, like d:\hearthstone etc.
Also ensure to extract Hearthranger rar file other than default [download] directory.
Bot needs full rights to access installed directory (read&write), game's directory (read), game's process (read/write), and game's registry (read/write).
Hearthranger has free trail time, you can use it to confirm it works or not on your system without buying it.
Don't worry we'll refund to you if you can not figure it out what's wrong in your system.
* if bot just shows slow mouse moving, you can speed up mouse movement in
[Task Editor] --> [Bot control option] --> [Mouse move speed].
or just turn [Show mouse movement path] OFF.