It's especially true for someone starting out as a bike commuter. He/she won't know what kind of bike is best for him. (Forgive me, but I can't keep up the him/her thing.) So start on anything. Then you'll know if you want a racing bike, a cargo bike, a folding bike, whatever.

Some bikes are close to ideal for some people and some conditions. Some are not. But a bike is a device for getting from one place to another, and a bike will do that, if it runs. Coming back from the other place to the first one is rarely much harder, so the same bike can perform that function, too. Once you've gone out and back, you've commuted. There: you're on a commuting bike.