As a piano teacher for decades now, I've often heard from parents of prospective students a statement along these lines: "We're not sure whether [our child] will like learning piano, so we want to start with a keyboard until we know s/he will stick with playing." Dear gentle reader, prepare for a controversial post to follow. :-) If I wanted to make this post super short, I could answer the question in my title, "No, it's not a good idea to start learning piano on a plain key