This 世界でも means 日本だけでなく、世界でも. = not only in Japan but also in the world.
で = in, も = too.
If you omit 日本だけでなく in this context, 世界でも implies that you want to say "not only in Japan."
ex, お金はコンビニでもおろせます。
This sentence doesn't say 銀行だけでなく, but it implies that you can draw money from other places too.