Most bounty and airdrops in this era can be said to be a waste of time, but not all airdrops in this era are a waste of time because it's not like it used to be that you just join and you have rewards to receive. The current style of those doing airdrops is that you first use their platform for a few months and do an activity on it. Then, all of a sudden, they will have a program of airdrops for qualifiers who just use their platform and trust to enter funds here.
As for the bounty, maybe it's possible to say that it's really just luck. Because if the managers who hold it are reputable, the rewards you will get are not that big. It was really only in 2017 that there were large-scale rewards in the bounty, to be honest, but this time I have not seen or heard anything like what happened in 2017.
Those days are never coming back, I remember reading several cases of people making full bitcoins with bounties, and while bitcoin was not as valuable then as it is now, someone that did that and held their bitcoins to these days should have made even more profits, however with the bad reputation icos and new altcoins got in general and the increase on the people trying to become bounty hunters, this suppressed the pay those people could get for their efforts.