Obviously that's a consideration, but this script has removed a dependency on checkip.dyndns.org. You could make the case that that's more likely to stay up, which is a valid decision.
Alternatively, you could create a "whereami" that returns the ip, and use that in your scripts. If ifconfig.me goes down for good, you have to change the url in one place. I'm sure you'll cope.
NOTE: If you visit ifconfig.me with your browser you get an html page full of text, but with the curl useragent it just returns the ip-address