Is there a reason to set a crawl-delay in the robots.txt?

[MichaelWeisbaum]

I've recently encountered a site that has set a crawl-delay command set in their robots.txt file.  I've never seen a need for this to be set since you can set that in Google Webmaster Tools for Googlebot.  They have this command set for all crawlers, which seems odd to me.  What are some reasons that someone would want to set it like that?  I can't find any good information on it when researching.

[NakulGoyal]

Google does not support the crawl delay command directly, but you can lower your crawl priority inside Google Webmaster Central.

So you are right using it the way you are. If you have it in the robots.txt, it does not really do anything and it will show in the webmaster console as well that GWT does not support it.