Even if you think police are necessary and are in favour of them existing, there's one very important thing to alway remember: their investigations are *supposed* to be slow and expensive. It's a safety measure.

Investigative techniques costing a lot of time and money to apply, without a lot of budget available, is one of the most effective ways to prevent overuse of them; to ensure that they are only used when they really need to be. It's one of those "checks and balances".

By arguing for "efficient policing" and "process optimization", what you end up arguing for in practice is for cops to be able to use these techniques indiscriminately without much thought, because the cost and effort is trivial. This is a really bad thing!