Annuals live one season and then they are finished, which is the honest trade and also the entire point. Nothing else gives you continuous color from the last frost to the first one, and nothing else lets you change your mind every year.
They earn their place where a permanent planting cannot work hard enough — containers at an entry, a bed against the house that is seen every day, the stretch of a commercial frontage that has to look deliberate from May to October. For a wedding, a party or a listing photo, they are the only plant that delivers on a date.
The honest version of what they cost is water and attention. An annual has a shallow root system and about four months to do everything, so it does not ride out a dry week the way an established perennial does — in July here, a container can need water daily. They want feeding, because the same speed that makes them useful empties the pot. And deadheading keeps most of them going; without it a lot of annuals quit in August.
Put them where they are seen and where they are easy to reach with a hose, and keep the permanent structure of the planting in perennials and shrubs underneath. Annuals are the layer on top, not the plan.