>>madars+(OP)
I think Graphene gets posted here yearly. Having tested a variety of ROMs dedicated to different elements of security, I can attest that Graphene allows the most "normal" phone usage compared to many others. The biggest factor is the sandboxed Google Play Services, which allow you to use a lot of apps that you wouldn't be able to otherwise.
I've used Lineage without MicroG, as a comparison, and that's becoming more-and-more unusable every day some lousy Android developer tethers their company's app to some feature exclusive to Play Services.