They are not 'pretty common' in investment banks. A tiny sliver of customer facing employees regularly work those 60-70+ hour weeks. Like a thousand people at someplace like UBS.
I haven't ever used a case on an iphone, and never once had any damage that impaired the functioning of the phone. Some scuffs and nicks around the edges, but for all the complaints they're quite durable unless you actually try to damage them.