0.03 mm would be really easy to break, yes … 0.3 mm should last longer 
This is one reason why I usually take my iPad to my modelling room. (The other main reason is to take photos of the model I'm building.)
Another good use of a tablet (or computer) is that you can look up scale drawings and measure things in them. If you zoom in until the size on the screen is the size of the model, you won't need to do any conversions — though with a tablet, you will need to be careful not to touch the screen with your fingers when you're taking measurements.