You could always make your own walking grids but im not sure why you would use the bot to gather before you have completed MSQ and got all the aether currants already.
Running a pure walking grid in some of the shadowbringer nodes would greatly increase the time it takes to actually gather them enmass as there are some that are very far apart. And honestly would look more like botting then if you did fly. The bots walking micro adjustments are much more obvious on foot then in the air.
That said you can also manually adjust the navigation grids after you imported them by turning on edit and turning all flying points to foot or mount.
And on a side note you probably could get miqobot to get aether currants for you but you would need to make a custom grid for that. You would just need the bot to walk you up to an aether currant and hit what ever key you have for select a target and confirm.