Exactly. Many "model airplane purpose built" engines use a flywheel and magneto. They work fine and for most sport applications they are perfect. If you have a model where you don't have room for the flywheel, can't have the extra weight, etc. then EI is for you. Performance gains are anywhere between 10% and 0% with EI Vs flywheel. On some models such as WWI warbirds the extra weight in the front is needed and would otherwise end up being lead.