I've never run across a recommendation not from an installer.
But in theory UV can be helpful if you have "significant" mold growing close enough to the input side of the evaporator coil. UV lamp selection and optimal placement are important.
Try asking the installer to take a before photo and another photo next service and guarantee a refund of there is no improvement ;-)
The lamp can be a high cost maintenance item.
And they can degrade any plastic or wire insulation in the path of the light.
Here's a relatively informative overview, also read the comments.
https://youtu.be/5K9pu-tkNYM