I don't think I would ever open carry, but I don't see it as a bad practice. The way I see it there are disadvantages and advantages to both concealed and open carry.
You need appropriate training to draw a sidearm from concealment.
You need appropriate equipment, such as a smaller gun or a concealment holster.
You have to realize that there is no deterrent effect, because criminals do not know you are armed. You may become a target because the perception is that you don't have a gun.
Element of surprise.
You can carry into places that might hassle an open carrier.
Criminals are less likely to grab your gun before a confrontation starts.
You need appropriate training to protect a sidearm from a grab or draw from a retention holster.
You need appropriate equipment, such as a retention holster.
You may become a target because criminals know you have a gun.
Your sidearm is arguably more accessible to criminals.
Some criminals will see you have a gun and avoid you.
Size is less of a factor in selecting a sidearm.
Sidearm is arguably more accessible to you.