The Automation engine right now is relatively new compared to the old infrastructure. Rules API (what the new automation engine is based on) works completely differently so of course the dev team has to change how some things work.
Over the last year theyve made SIGNIFICANT progress bringing the capabilities of built in automations to be on par with what one can do with Smartlighting. (read its work in progress, and why you haven’t seen Groovy completely removed yet). Automation that needs two pieces to work is minor. There are plenty of functions that dont have direct equivalents yet.
There is a rumored rules builder coming “soon” (probably a lot sooner than Groovy retirement) to help build more advanced automation (ala webcore)
Whether completely on parity yet or not CERTAINLY wouldn’t go backwards