TinkerCAD's forum is very limited on how to ask questions (with only pictures). And it looks like questions are replied to weeks later (i.e., low traffic).
I have a pretty simple question about using a slide switch in online simulation and IDE. What do you think?
Really the fact that it's an online simulation is irrelevant. The issue in question was with your code, and it would be the same on a real Arduino (lack of pullup / pulldown resistor on the input, or no INPUT_PULLUP set).
In this situation the question is not really about TinkerCAD - it's about your code or circuit.
However if there was something that worked on a real Arduino but not on TinkerCAD, you'd certainly be better asking about it at TinkerCAD.
