The downside of the coating is in the initial investment and overall process of installation which is traded for the peace of mind of not having to wax and polish your car every few months to keep your car protected, and years of easy cleaning.
As Ceramic coatings are designed to last for years and not months unlike wax and sealant options, the initial investment is higher with typical prices for a quality product and installation usually between $1000-$2000.
The initial installation can be quick finnicky especially with the longer lasting coatings as they are a more permanent bond to the paint work so you want to ensure it’s done correctly.