I'm also not a fan of physically separate bike lanes.

• They're like riding on the sidewalk:
  • Vehicle drivers never expect to interact with you, so as vehicles enter or leave the roadway via driveways or cross streets they often don't even notice the cyclist in one of these separated lanes. You are not part of their world, until you suddenly are.
  • People may be walking on them.
• Manhole covers and other maintenance equipment get placed inside them and they're narrow enough that it's hard to dodge these obstacles. Because it's not the main road, workers tend to accept a lower standard of smoothness.
• If there is some construction on the road, these are the first parts of the road to get blocked.
• They can fill with debris and street sweeping vehicles don't fit to clear it.
• Occupants often have no expectation of maintaining a traffic-like flow, so other users become obstacles too.

On the real road vehicle drivers do have to interact with you; you're part of their world. You are less invisible to them, so they're less likely to turn suddenly or pull out suddenly in front of you.

People are less likely to be ambling along in herds in front of you.

Other users do have an expectation of riding/driving in road-like conditions, so they behave predictably and are less likely to become complacent obstacles.

Now I really hate being forced into a lane to the point that vehicles can't safely pass me. That's a recipe for impatient hostility. But I do prefer being on the road where I'm part of the flow.