Why is the definite article used in the German version? Is it actually necessary?
I am not German, but I know that in German, the definite article is used more often than in English, and in places where it doesn't make sense to use it in English. For example, my name is Samir, and in English I would say: "I am Samir", but in German I would say: "Ich bin der Samir". In English, saying "I am the Samir" would imply that I am some famous personality, like "THE one and only Samir", but that is not the case in German. Every language has its idiosyncrasies :)
It's more common to ask ‘Bist Du der Samir?’, or say ‘Das ist der Samir’ than to say it of oneself. Often, the definite article means “the one we were talking about.”
I've never heard "Ich bin der Samir" used. I'm not a native speaker though, so maybe someone else can comment. I've only heard "Mein Name ist Samir", "Ich bin Samir", or "Ich heiße Samir".
Newer German learning methods and books seem to avoid using the der version probably to make it easier for new learners, as German would appear closer to English that way. That might explain why you have never heard it before. Also, the Germans themselves seem to be using the versions without der more often, probably due to globalization. But if you watch German TV or play computer games in German, you will still encounter the der version. I also asked a cousin of mine from Austria, and she says they still use it, but not as often as they used to.
I am a native speaker of Geman and I can confirm that it is actually quite common to say "Ich bin der/die (name)"
I've heard that articles before names are more common in Austria, than in Germany. I've seen them in Christine Nöstlinger's stories (she is an Austrian writer) and the teacher told me that it is common in Austria, but not in Germany
Yes, German months and days of the week are generally always used with an article or other determiner, except when preceded by another noun, such as ‘Anfang März’ = “[at the] beginning of March”, ‘am fünfzehnten März’ = “on the fifteenth of March”.
Here in the US, I go to a German language Meetup.com group. I have heard one of two people use the definite article when introducing themselves (ie "Ich bin die Emily".) I also heard it used in a German video series for German students. (ie "Ich bin der Daniel.") I'm still not sure when it's used, so I have decided not to try to use it myself.
What is the more usual way to introduce yourself in German? Is it "Ich bin (die) Emily" or "Ich heisse Emily"?
Idiosyncrasies are distinctive or peculiar features or characteristics of something.
"The March is the month" is what it tells me is correct. That does not make sense in English. For the umpteenth time I fail a question because of poor translation on behalf of the site.