> My guess is that all those who are actually useful will get "grandfathered in" by this legislation making them life peers

The government made a political deal with the hereditary peers-drop their fight against this bill, and in exchange the government will grant a subset of them life peerages

But that political deal is just an informal extralegal “understanding”, it isn’t actually in the text of the bill-having the bill text grant someone a life peerage would upset the status of peerages as a royal prerogative, and they don’t want to do that