Why do you say it's a waltz? The intended audience is clearly not ballroom dancers.
You might argue that anything in "waltz time" is a waltz, but then your argument becomes circular. You would be saying it's a waltz because it's in 3/4 time and it's in 3/4 time because it's a waltz.
For what it's worth, it's quite easy to dance a waltz to the song. It's got enough of an oom pa pa that a waltz is very natural.
Possibly it makes more sense to musicians to notate it as 6/8 because the triples come in pairs. It's still a waltz though, and dancers' instinct will be to break it into triples. It's not hard to scramble a 6/8 signature to make it not a waltz (don't put downbeats every three, and it isn't a waltz) but that song definitely doesn't do that.
I have no idea what the intent of the artist is, but it's worth noting that the overwhelming majority of rock music is in ballad meter, not 3. So this is extremely unusual music for the audience this artist usually plays for.
For this piece, I think it's a waltz because it's in 3/4, at a typical waltz tempo, and it "feels like" a waltz, which is to say that the emphasis on the beats and their precise timing feels like waltz music usually does.
So no, I would not argue that anything in "waltz time" is a waltz.
Well, my whole argument was that while it superficially "feels like" a waltz in some ways, it's clearly in 6/8 because of how the underlying beat is grouped. That's what matters.
Just as a sanity check, I decided to look up some sheet music and see how others have interpreted the song. Every single one that I can find notates it in 6/8 (interestingly with some individual measures in 9/8).
The overwhelming majority of waltzes are notated in 3/4 with the measures in pairs, because it takes 2 measures (6 dance steps) to do one rotation of a rotary waltz. The two downbeats are equal. The music video on YouTube of Seal performing this song has equal downbeats.
If you write it in 6/8 instead, many musicians will emphasize 4 less than 1.
I think that dancers knowing music and musicians knowing dance is extremely useful. It changes your opinions about notation.
It certainly has the feel of a waltz. It's not that hard to make a 6/8 time signature not sound like a waltz (as you say, just hide the second down beat, or move it). But it's very very easy to waltz to the song.
Whether it makes more sense to musicians write it 6/8 or not, I have no idea, but it's still a waltz.
