Re: Lies, damned lies, and statistics that don't lie.
Mostly it is the last thing you want do. You want ping, traceroute and DNS working just to be sure your public facing services are up.
DNS is out of my hands, handled by my domain register (and internally, the web/email/VPN servers don't actually need DNS to talk to an incoming connection, and I could probably use no DNS and just a hosts file for the things I want them connecting to as outbound (OS updates etc). I cannot recall why I disabled ping but I've been able to tell if systems are up with very simple checks - does the web browser display the expected page, or is an error thrown up? Is the error server-generated (eg 404) or browser generated ("the site at xxx.xxx is taking too long to respond")? Does the email client get emails? If not, does telnet reach the client (see - ping would tell me the router can be reached, telnet reaches past the router, past the firewalls, and into the very bowels of the email server - unless it's borked in which case ping would be worse than useless (of course I could pass ping through the router to a server, but which server?????). Likewise VPN - does the server respond? No? Then it's down or my ISP changed IP on me (another machine in the house has a connection to mega.com, and a little script on that checks the IP every few hours and updates a text file as needed - the changed file uploaded to mega and pushed through to my other device where I can log in to the registrar and change things there).
Maybe it was Gibson who taught me to kill Ping off many many many many many many years ago... Point of the waffle above though is that I don't need any of those things to tell me if the service is up or down. Knowing they're down is as easy as seeing if they respond, and only a tiny part of the problem, and I usually have a few ways to tell whether it's a machine or the whole lot.
But most addresses are not servers. They are ISP home routers with NAT.
Given the large corporate and other walled-off chunks, I'd suggest most addresses may not be such. Most in use ones however...
How do you expect your ISP to provide support if you block ping?
Also not been a problem. They have several other ways of knowing if you're connected or not without pinging your router. Hell, mine were even able to tell me the fault was a damaged cable between the cabinet and the exchange which they then got someone out to fix pronto, once they'd been notified.
The few times I've needed ISP support, they've had no issues with things not responding to ping. I've been with them for the better part of a decade so that's probably 5 support requests (3 or 4 of which were due to that faulty cable!). If my router is connected to their system, they can see it's there. If it's not connected, no amount of PING is going to tell them anything.