yeah that’s right, there was a requirement at initial stage of making this part of UI we wanted to show the dotted line going through circles thats why created the guidelines. Kept it demonstrate use of Guidelines so that others can get idea about it
Working on RecyclerView from last few year this is good way but will give performance issues if number of child items are more. I was working on an app where I used similar approach it was causing lots of performance issues where child items count was more than 100 in my case. Although good approach if number of child items is less than 20 or say 25.