Copy & paste vs new layer via copy

Hi everyone

I've got a slow period at work so thought I'd swat up on some Photoshop tutorials. Probably a silly question but I came acorss one guy's tutorial who did command J to create a new layer from a selection he'd made, I've always done copy and paste which also creates a new layer of my selection. I admit there are less keys to press with command J but is there any difference between doing that and copy and paste? Have I been doing something wrong all these years or just doing it the long way? haha