The ISP cannot say you had this address, but only your computer. With public Wifi, several people will have the same IP address. The possibility of being hacked or having someone "borrow" your connection are also possibilities. Households, businesses, and schools may share a computer.
Sharing a fingerprinting, hacking a fingerprint, or being away from your fingerprint for a short period of time is nearly impossible. Your fingerprint is intimately associated with you, therefore the link to your identity is stronger. The law doesn't have to enforce this link because it is natural, biological. You are the owner of the fingerprint.
The danger with treating IP addresses as a strong link to a person is that a court is effectively legislating that IP addresses should be tied to a particular person who is responsible for it. That means you cannot share your IP address with others and cannot share a public computer.
Sharing a fingerprinting, hacking a fingerprint, or being away from your fingerprint for a short period of time is nearly impossible. Your fingerprint is intimately associated with you, therefore the link to your identity is stronger. The law doesn't have to enforce this link because it is natural, biological. You are the owner of the fingerprint.
The danger with treating IP addresses as a strong link to a person is that a court is effectively legislating that IP addresses should be tied to a particular person who is responsible for it. That means you cannot share your IP address with others and cannot share a public computer.