yep play services is the one thing that ties it all together and is the crucial part of gapps and the minimum of gapps installs. i have used custom rom without

yep play services is the one thing that ties it all together and is the crucial part of gapps and the minimum of gapps installs. i have used custom rom without googles stuff(including services). i was fine for my use case as i do not rely on google for my workflow.