Someone correct me if I am wrong, but I think what you are seeing is that in 2018, you could only place one dimension at a time. Then there were extra steps if you wanted to add text, or change a style, etc. And you could only do one dimension at a time which was a slower process. In 2019, the new feature allows users to continue dimensioning without ever having to leave the smart dimension tool. It is so much quicker and fluid to be able to stay in the tool and has saved a tremendous amount of time when adding a lot of dimensions onto a sheet. I know this answer probably does not help with not liking how it is handled now, but my hope is that it at least helps explain why the change was made.
RJ