Are you thinking about Recovery Runs wrong? (probably)
"It is my opinion that recovery runs as most people think them do not exist" - Click to Tweet!
When it is the evening or day after a hard/long run and you're a bit tired, going out for an easy half hour on tired legs is not going to enhance your recovery.
That would be like doing more bench pressing after a hard chest workout, it's not speeding up recovery. However, that does not mean they are not useful!
Recovery runs, running easy on tired legs, is a further stimulation for adaptation just as a workout is. All running is a workout, some are just more difficult than others.
When you do recovery runs you're simply getting more fit! Your body is getting stronger and you're eventually over time able to run better. This is why I refer to what would often be called a recovery run as a "Tired Legs Run" for my athletes.