Maida was certainly important for England. I never heard of it before diving deep into Napoleonic history.
Do you have testimony for its importance outside Sicily and United Kingdom ?

Although it doesn't actually address Maida, to more fully appreciate the importance of Naples/Sicily to England, read "counterpoint to Trafalgar" by Flayhart

Maida results in a huge strategic setback of several years for France's effort to seize Sicily; this was important, see "The War in the Mediterranean, 1803–1810"

It's my understanding that Wellington studied Maida in detail and even applied some of the lessons learned in Spain. Many officers from the battle are said to have been prominent in Spain.

Of course, later events completely overshadowed Maida, but it was the first ever defeat on the continent of a Napoleonic army by an English army, so, no matter what, it was a significant event. It was in all the papers. Gilray summed things up: