Yes. For example, if you wanted to tell a stranger "that person is a police officer," the most natural translation is probably "ano hito wa keikan desu." In other contexts, you might replace "desu" with the informal "da" or the ultra-polite "de gozaimasu" (or "de gozaru" if you're a samurai). In practice you wouldn't say it too often. Other grammatical structures (like "-te iru") are more appropriate counterparts to maybe 75% of English sentences involving "to be."
It is nonetheless grammatically possible to contrive every sentence to end in "desu." This is an unusual habit, though. It's a little like beginning every utterance in English with "it seems" or "Simon says."
です？ Wikipedia says: "word used to grammatically link a subject and predicate, often translated into English using the verb "to be". And, yes they do use it. But what is strange about it?
Do English really use "to be" (in its various conjugations)?
There's an anime character who ends every sentence with です (as I described above). GP is probably referring to a famous internet meme where that's the only word she knows.
It means "is", so yes, they do. It's used for predication instead of existence (iru & aru are for existence), but that's probably the more common is in English as well.
If you want filler, it's when people are going え～と while trying to collect their thoughts.