After the success of Notecoin, telegram airdrops became very popular and attractive. It seems that's the new trend and it might last until the end of the bull run. For sure many of them will end up becoming a wasted effort.
Not all projects would end up successful even if it isn't on telegram but I actually don't mind putting in some efforts. It is not that time consuming nor too complex to do.
My position is that you don't have to put all your hope in them to make money. Use them for fun and get these airdrops. If they end up becoming profitable you celebrate your success.
I think this easily applies to all kinds of altcoins. Do not put all your eggs in one basket. It is still nice to try since you will not lose that much.