I remembered you have already asked this type of question
before. Maybe you need more explanation.
With watch only wallet, you only import addresses or master public key. Addresses and public keys be it child or master public keys can not be used to spend from a wallet. You will need the private key to spend.
Addresses starts from: 1, 3, bc1 while master public key start from xpub, ypub or zpub
But you actually need seed phrase, master private key or private key to the corresponding funded addresses to spend from a wallet. Or if you have the wallet file, if not corrupt, you can also use it to recover keys generated by your wallet and be able to spend.
The master private key will start from xprv, yprv or zprv. The private key to corresponding addresses will start from K or L. Or 5.
It is as easy to understand as that.