The distinction seems to have arisen, or was at least encouraged by, sectarian tensions.
To clarify any ambiguity: If you describe the Arahant, as defined by Theravada, to a Mahayana Buddhist, without using the term or explicitly distinguishing it from a Bodhisattva, what you would have is a bodhisattva. And if you describe the Bodhisattva, as defined by Mahayana, to a Theravada Buddhist, without the specific sectarian semantics, what you would have is an Arahant.
The examples used to distinguish the two aren't concerete, because they're abstract descriptions of mystical abilities, which I don't doubt the existence of but consider pretty irrelevant any meaningful discussion, outside of "what traditional Theravada\Mahayana Buddhists believe". But if you break it down to something simple and concrete, like great compassion, great wisdom, great morality, etc., there are no significant differences.
To demonstrate this point more clearly: Buddhist schools pretty much agree what a Buddha is.
Well, in Theravada, Arahants are in some ways regarded as equal with "Buddha" (the Buddha himself is called an Arahant), but in other ways below it (the Buddha's knowledge and power is apparently greater than the other Arahants, the simsapa leaves metaphor demonstrates this, I think, and the ten powers of the Tathagatha too). And in Mahayana, Bodhisattva is in some ways regarded as equal to a Buddha (the terms are sometimes used interchangeably, as celestial bodhisattvas are referred to as Buddhas) but also lesser (since a bodhisattva is technically regarded as one striving to become a Buddha).
The best things in life aren't things.