I second this. If Checkboxes and Checklists are different, and we choose to use a Checkbox (by the cumbersome new Insert method), why would the program designers think that hitting Return/Enter would mean we want to convert it to a Checklist.
I miss the old functionality, and request that if I enter a Checkbox, then hitting Return/Enter should actually start a new line with a new Checkbox.
In my daily use, and in both Templates and many current notes, I use a Checkbox to indicate an unanswered or uncompleted item. When completed I typically check the box and enter text at the end of the line, in a separate font. This lets me know what the answer or resolution was. In Checklist mode, this "resolution" text is also struck through, which does not delineate it from the original question, task, etc.