Airdrops is worst way of doing the marketing and bringing people on board because I believe that it doesn't work at all. Airdrops are just worst way to promote ICO because millions of tokens are spared in the air at the cost of nothing. Mostly people collect these tokens and immediately starts dumping it when they get it listed over the exchanger. ICO funds also get diluted due to this act. People dont care if they bring the real people on board or just the fake accounts and thus where Airdrops should be getting more organic traffic there it gets only may be 50-60% organic advertisement and most of them are dumpsters too.
Dont even know why these guys go for it.
Beside that they could put extra funds on developing their products.