I think it's very dangerous to go all in one project. I prefer to invest $50.000 in 5-10 ICOs instead of one. And about Bitbose.. such big bonus is red flag for me, I will skip it.
Yes, whether it is a crypto investment or any other investment one shouldn't invest all their money in any single coin or a product instead they should diversify their funds to reduce their future risks. If one or two coins don't perform as per our calculations still we can a decent profit in the long run by diversifying.
If one is offering very huge bonus means they failed to market their product so they are offering huge bonus so that they can just get as much as money from the investors but once these coins come to exchange then its prices will go down a lot due to no buyers. So buy only high demand coins not the other way round.
Since we are talking about a huge amount of money it makes sense to invest in more coins however if someone already has that amount to invest it does not make sense to invest in risky icos after all if you select the wrong ico you could lose all your money it could be a better idea to invest in the most established coins in the market, the profits are not going to be that good but the risk of losing all your money will be very low.