When you are working on any kind of project, you should globalize it. Except if you have a very specific target audience of course. The importance of globalization in general is enormous.
More than Localization
When we are talking about globalization we are talking about much more than simply localization (which would mainly consist of translating your program). You could say that globalizing your application would mean to make it accessible to users all around the world.
Does your program come with any kind of currency handling? Guess what, you should add support for foreign currencies. Another marvelous example: date formatting! Worldwide there are quite a few different date representations. Make sure you display dates in a matter that your end user is used to.
Try to view the big picture. Apply country-specific standards (representation of VAT numbers, bank account numbers and specifications, address (and zip code) notations, …) as often as possible. But be aware of one downside: data conversion might be needed in some cases. Make sure you are prepared for that (foresee some good old converters).
Increased Target Audience
Imagine what impact a proper globalization implementation might mean for your target audience. Guess what, it will vastly increase and thus result in more sales. Now go improve your conversion rates!
Is it Worth the Effort?
I can already picture programmers and project leads thinking why they would even bother to put in the extra effort to globalize their project(s). Globalizing does indeed take up some time. In fact, you could say most of the time would have to do with the initial setup. Once you get it going, you only need to update your existing resources every once in a while.
The extra effort put in should not be a factor. The value of your application(s) improves so greatly that this minor efforts are really no argument for not having a globalized project. Don’t argue and do it already!