You will have 24 hours to confirm the email validation link. If you do not confirm it within 24 hours your provided data will be deleted. In this case the chosen account name and used email address will no longer be saved. You would need to register again.
After successfully validating your S&F account you will be able to login and to create new characters. Those characters will be validated and connected to your S&F account automatically.
You will only be able to purchase mushrooms and sales packages at the mushroom dealer once your character was validated. If you connect it to your S&F account it will be validated automatically and you will get 15 mushrooms for free booked that specific character as a small token of appreciation for connecting it to your S&F account.
Long story short, it is important and beneficial to validate your S&F account to be able to automatically connect and save characters in the future.