Just my opinion but I think the benefits are relatively small. Are there benefits? Yes. Will the average rider notice them? Probably not. If you are entering a boarder cross event where the difference between winning and losing will be measured in seconds or sub-seconds, then yes temperature appropriate wax and other performance/tuning tricks may be advantageous. If there is a 10 degree temperature swing that reaches across two different temperature waxes and you'll be riding groomers and park on your local mountain, probably a situation where you will not notice a significant impact. That is not to say you won't notice some change, just not a significant one to make worrying about it that big a deal.
For me, I like tuning my boards so I'll wax them quite frequently through-out the year. Probably more than is needed but I enjoy spending the time waxing, scraping, tuning, etc. and for me it is just a part of the ritual of snowboarding. Drinking few cold ones while doing it also helps.
So I'll take a look at the forecasts, take an educated gamble on approximate temps and riding/snow conditions for the upcoming weekend, and I'll use the temp appropriate wax. Am I fooling myself that it actually matters for my style of riding? Probably but I enjoy the hell out of it so who cares.
Just a tip - If you have a local shop, talk to them about waxing techniques, etc., to learn a bit before you start doing it yourself. It is not terribly hard but there are some simple mistakes you can avoid that at worst will make it easier/quicker and at best save you from damaging the base of your board. There are good online resources to for waxing/tuning if you don't have a shop nearby.