At the moment I have the same impression, but I'm open to a change of mind. There are several seeders of a similar design on the market. One which looks to be a possible proper tool is the "Pro Seeder". This appears to have several nozzles to suit different seeds, and I think it sucks a seed onto the nozzle, then you squeeze the bulb to release the seed into position.
I have seen commercial seeders which can do tens of thousand seeds an hour, they have attachments which are seed-specific, so a does-all seems unlikely.