Jury trials are a colossal and disproportionate waste of time. Jury trials have it place, but most of the time is spent on jury selection, theatrics, and deliberation--all this cost dearly, both in terms of time and money.
Thanks to its high cost and unpredictability, laughable inventions like "plea bargains" exist, only to selectively prey on the vulnerable.
It's not perfect (nor are jury trials), but when it comes to truth discovery and arriving at a proportionate sentence, as long as all parties are fairly represented, one without jury trials should be just as effective.
UK trials don't spend lots of time on jury selection. And there's rarely days of deliberation.
Not everything is done in US style.