As a poster above said, generally there will be bonuses during an ICO and usually a better bonus at an earlier stage.
The Novatoken ICO for example started off at 60% bonus and dropped at each stage down to 50/40/30 etc. That should, therefore, give you an advantage over any market price and covers for the coin dropping (people dumping as soon as it gets to market) once launched.
A lot of coins/tokens of course aren't in it for the trading of the coins or the market - they are in it for the solution and for using the blockchain as a technology to solve a problem - Novatoken for example allows ownership of electronic trading cards, you get a card and you own it - and you can then trade it in an in-game marketplace using Novatokens. The more NVT you earn the better and more cards you receive - common/uncommon/epic/legendary. So you can see there's a benefit to holding the tokens rather than selling. It will be fascinating to see how the market reacts and is influenced by the dynamics of this - and of course the platform isn't restricted to the one game.
More information here:
https://novablitz.comhttps://t.me/novablitzThe ICO finishes on the 31st January and so it won't be long before the above is answered.