[Silhouette]

The point is that trademarks have to be meaningfully defended or they can be lost.

Claiming something as a trademark or registered trademark, particularly something new that doesn't yet have a strong brand associated with it, is one possible element in establishing that defence.

There are others. If you set up a new business selling mobile devices called iTelephones, it will probably not be long before you get contacted by Apple's lawyers, whether or not the term iPhone has an accompanying annotation on their promotional work.