Two philosophies
Blurred lips treat the border as something to dissolve. A lip-liner tattoo treats it as the whole point: a crisp, defined edge — occasionally slightly overlined — with the natural lip left mostly bare or only lightly tinted inside.
Ageing
The liner look repeats the historical problem: the line is the most saturated part, so it is the last to fade and the first to migrate, and 'liner plus faded centre' is an unmistakably dated result. A blurred lip has no such failure mode.
If a client wants definition
Steer toward an ombré blush — a band of higher density at the border rather than a drawn line. It gives 80% of the 'defined lip' feeling with none of the doughnut risk. Reserve true tattooed liner for clients who understand and accept the maintenance.
