Yes, you can clear both Cache & Data for the Smart Switch app, you can also uninstall it if you want.
You will NOT lose any of the data currently on your phone.
That is NOT what they are asking!
They are asking if Clearing Cache & Data for the Smart Switch app, would delete anything from their device, not the app.
AND, the answer to their question is, NO, nothing on the device's storage will be touched by Clearing Cache & Data for the app.