In the phrase "better off," "off" is necessary because "better off" is a common idiomatic expression. It means to be in a more favorable or improved situation. Simply saying "better" without "off" wouldn’t convey the same meaning about a person's overall well-being or circumstances.

In the phrase "If you choose me as leader, we would be better off," the word "off" is part of a common expression "better off." This phrase means to be in a more favorable or improved situation compared to the current or previous one. The word "off" is necessary in this idiomatic expression because "better off" conveys a complete meaning. Without "off," the phrase would feel incomplete. For example: "Better off": In this context, it means the group would be in a better position or have improved circumstances under the speaker's leadership. "Better" (on its own): Simply means an improvement but does not convey the same idea of being in a more favorable state. So, in this sentence, "off" helps clarify that the situation would improve in some measurable way, and it's commonly used in English to talk about changes in people's situations, often related to well-being, finances, or general circumstances. In short, yes, the word "off" is necessary to complete the phrase and make it idiomatic.

In this sentence "off" is part of the common expression "better off." It means being in a more favorable situation. The word "off" is necessary in this context because "better" alone doesn't convey the full meaning of improvement in circumstances or conditions.

It's just a common figure of speech. Given the choice between "we would be better" and "we would be better off", every native speaker would say "better off" to make it clear they are referring to being in an externally better situation, rather than referring to internal self-betterment. There's no great logic behind it, it's just the traditional way to speak.