There are never no strings attached. At the very least there are social expectations. Some people feel expectations very acutely and try hard not to set expectations they aren't sure they can fulfill.
> if you could raise a seed round while giving away a minimal amount of your company and not giving away control, why wouldn't you?
You have no idea when or if a liquidity event might happen or how big it might be and you want to make as few promises as possible to keep your options open, including holding no substantial assets at all.
You don't want to add another person to the list of people you have to loop in to conversations.
You don't want to leak information into the tech establishment.
You expect big dilutions later on and you want to keep as much equity as you can initially.