Unfortunately banks in practice do the same, they just don't disclose it. Wise will give you a better exchange rate (the "real" one I believe), but you will have to pay a, unfortunately, percentage based fee for the transfer.

Banks will give you a worse exchange rate, which in practical terms means you will lose a percentage based amount on the exchange rate, but fee for for the transfer is not percentage based.

So the question becomes: is the percentage fee Wise adds to the transfer smaller or bigger than the percentage fee banks add to exchange rate? I am not sure about really large amounts, but for the smaller amount I've compared Wise's percentage fee is lower than the banks percentage fee.

Another benefit of Wise is that you can see the what the exact cost will be /before/ you do the transfer. For large amounts you may be able to contact your bank and ask for a guaranteed exchange rate, and then compare that to Wise at real-time. I belive you can also contact Wise and negotiate a discount, but I have not tried that.