Painted lines can be both very good and very bad. It really depends on implementation. A painted strip right through the door-zone of parking is the well known

Painted lines can be both very good and very bad. It really depends on implementation. A painted strip right through the door-zone of parking is the well known example of bad painted lines. But painted lines next to a pair of narrow lanes are bad even without parking: here, without the bike lane a cyclist would effectively take most of the full lane, with overtaking cars easily doing a half-width zip merging on the outside lane. It's an easy flow with cars temporarily "compressed" onto "1.5 lanes". But when you compress the cars onto two permanently narrow lanes, with an explicit bike lane, drivers will reliably stop the zip merge and just plow through, often even much closer to the bike lane than to the other car lane. The worst examples are those where the original road was slightly too narrow to make 2x car and 1x bike and they painted a minimum width bike lane: on those, drivers keep doing double file and those on the right routinely enter the bike lane - and they still don't do the "partial zip" they'd do without the bike lane. Those things are not only worse than fully separated, they are worse than absence of bike infrastructure. But a not-bad lane implementation (either enough room for well-sized lanes for both cars and bikes or making the remaining car lane clearly too narrow for double file), yeah, I'd take it over fully separated any single time. Much better coordination with right turning traffic (occasionally, when speed happens to match, I even merge through the right turn lane so they don't have to give me right of way, clear win-win), much safer access to left turn lanes if you need it, much easier merging into traffic when the bike infrastructure is blocked (plenty of occasions, both sides of legality) and in general sooo much less interaction with stray dogs, children, cyclists who ride against traffic because in their mind they are a pedestrian with wheels instead of a very light vehicle, pedestrians who walk there because in their mind they are cyclists (yeah, that has happened to me, I admit) and so on. I love painted lanes! Just please avoid those horrible mistakes that you have to avoid while setting them up when you set them up.