I guess practical is a term that changes somewhat based on the level someone is at. As more of a beginner, the book looks great. Eg, for a beginner it's highly practical to learn how to read resistor bands or calculate Ohm's law.

Whereas "for Inventors" seems a bit of sleight-of-hand marketing. Beginners in the field may also identify as and aspire to be inventors, making a more broadly-appealing title vs "for Beginners", though it may have been more accurate.