The average contactless transaction is under £10, so most people are going to get 10 or more transactions between PIN prompts.
I did some explaining over in the labs topic (linked below) when we rolled out a preview of these changes into labs, but in summary UK terminals don’t and are not permitted to support contactless and PIN
If you wish to avoid having to insert your card periodically, we’d encourage use of Google or Apple pay, which are unaffected