To say another star has an exoplanet seems redundant. Why not just say it has planets?
For practically all practical purposes, everybody who uses both words "planet" and "exoplanet" in practice, the difference matters. Language is a tool, and it is practical to have words which are a compromise which between avoiding ambiguity, being short, being consistent, and being practical.
For example, now and at least several decades into future, you can resolve the disk of "planets" with telescopes, and even see most of them with Eyeball Mk1. Contrast this to "exoplanets", at best for a few cases you can capture a few photons you can be pretty sure came from the "exoplanet", and this is not going to improve much until most if not all current IAU members, who decided on the terminology, are pushing daisies.