using K&N filters is an investment.
so if you look at it from an engine performance perspective it wont give you much benefit (as in hp increase) however reducing the filter resistivity - as in reducing pumping losses will increase efficiency and therefore will somewhat increase fuel efficiency (edit only at WOT as its pointed out so I’m pretty sure you don’t floor the car on public roads so I’m retracting the cost savings comment). would those savings translate to the additional cost of the filter - well it depends on how many miles you do per year. Also if you invest in K&N you have to invest in the cleaning detergent and you have to apply the red oil on the filter. Because the filter is less restrictive the car has nicer induction noise over the stock filter.
so to answer you question does it worth the extra cost… well it depends on what kind of person you are (petrolhead or not) and whether you consider a K&N filter too expensive. I have one, I use K&N in my cars regardless. However it won’t magically give you +5 hp but two stripes on the side of the car will (+6 hp for each stipe I’m told)