Is there a limit how many times we can win in 1 day?
As per his rules, A single address can only win once in case you won multiple times in a day, The lowest prize that you draw will govern as reward and disregard the rest. Meaning if you get 1EUR on your first draw then got lucky to get 25EUR on the second draw, You will only get 1EUR as it is the lowest amount.
This rules will just make this faucet not friendly for user. But I don't have the right to comment on that part.