True, spending time hunting down some Airdrops is a waste as not all of them pay off and also not all of them can be of value as expected, so Airdrops are not a job to be hunted like the others, even if you have spare time to hunt them.
Hunting for airdrops is not a wasted job but something in vain is if you join thousands of airdrops without analyzing project quality, many new scam projects add community members with airdrop programs to lure investors into fake sales. If you don't want to waste time, join less than 10 airdrops of quality projects.
Analyzing the project takes your time, and if you have no good knowledge about such project then it will be just wasting time even worst. How to make make participating in airdrop as something which is not wasting time? It is simple, just do it for fun on your free time and do not hope too much from the airdrops.