Is it appropriate to use System Usability Scale to measure a KPI?

On several sites I find people recommending the use of SUS as a key metric to keep an eye on.

I can't really find any information on whether people use it continuosly to measure a KPI (in this case, the KPI being measured would be perceived usability of the website).

The tool/ website in question is a client web with limited new traffic and the use of SUS would mean probing the user base with SUS a few times per year.

Any thoughts or insights into this would be greatly appreciated!