Black & White SOOC or filter?

I was curious if there was a true difference between shooting B&W straight out of the camera versus converting to B&W in post? Is it not just a filter either way?

For context, I thought I would enjoy street photography, but I always end up pointing towards the buildings downtown and not the people. I tend to shoot in color but find myself adding a B&W filter and am curious if I am losing image quality this way?

Thank you!