I am always weary of ICO's that are willing to give out 50%, seems like they don't actually value their token at all.
It is more about stimulating early adopters. I wouldn't see it as giving away tokens that they don't value. I would rather see it as giving a lower price to early adopters. This way they have a big community backing it already from the first days/weeks of ICO. This worked very well for Electroneum, as sales increased massively everytime a certain bonus percentage was expiring. I expect the same to happen for Heardbeats as there is a very solid projec that is backed by a great proactive team
But 50% as a bonus is going too far, I could understand 10% or even 20% but to go that far it really gives the impression they want to grab as much money as they can and do it fast, after all if they were so sure about their project they will not need such bonuses, and about the idea I think this is something novel and that is always a good thing but I do not know if it is going to work.