To what degree is protective domain name registration useful?

Hi, we are a startup company from Boston, MA. To secure our online presence and protect future global expansion, we would like to strategically reserve domain names for our company name and our products. Besides registering the names as such in different jurisdictions (e.g. google.com, google.ca, google.jp, google.eu ...) -- should we also register similar sounding names (e.g. goggle.eu, doodle.eu, googel.eu)? To what extent would this be necessary? Does it even provide any meaningful protection of our brands?