[Klaus]

I've just watched a video where, as so often, a variable max aperture was mentioned as a negative.

I, for one, never had an issue with a variable max aperture ... ever.

I get that a faster max aperture is better than a slower one, but this relates more to sophistication ... and, consequently, the higher price you have to pay for the privilege. 

e.g. I'd rather have an 18-55mm f/2.8-4 than -say- an 18-55mm f/3.5. 

So what's the point?

[stoppingdown]

I totally agree. I think it's a legacy from the old times.

[wim]

Variable aperture zoom lenses often are created for the 'user' category rather than the 'pro' category, what often means that such a lens does not perform like a fixed aperture lens.
That is how it used to be, in any case, and it still holds now, at least to a certain degree.

However, the example of fixed aperture F/3.5 vs variable F/2.8-F/4 seems to indicate 2 lenses in the 'user' category. In that case it just is whatever you prefer, fixed aperture or variable, obviously depending on the IQ of the lens as well.

Personally I prefer prime lenses for optimal IQ, as I do not necessarily need the ease of cropping by means of a zoom, which for most people is the way they use a zoom lens, rather than as a lens with a variable set of fixed apertures.

[Kodachrome 25]

As I prefer manual exposure for most of my shooting be it static scenes or even kids against strong backlight, I would not be happy with a variable aperture standard zoom.
And indeed, the 75-300 4.8-6.7 ist the one lens where I sometimes switch to aperture priority mode with iso on the second dial.

[thxbb12]

The only reason I can think of beside what was written earlier is for systems that use aperture rings such as Fuji.
With a constant aperture lens, the aperture ring can be marked and you see exactly what aperture you're using without having to look into the EVF.

[Rover]

I don't care a great deal since I'm shooting in aperture priority 99% of the time anyway, and usually stopped down. In cases where the smaller max. aperture at the long range of a zoom lens is the only (realistic) way of making that lens possible, like with the 100-400mm f/4.5-5.6 class, I'd very much prefer that to - say - straight f/5.6. Not just because I'd want to shoot at f/4.5 much, but because I hold an old belief that faster lenses are better for stopped down shooting too, since I'd rather stop down (the usual) 1-2 stops from f/4.5 than from f/5.6.

With today's uber slow lenses, variable aperture is an incentive too - I'd rather have fast (or at least not dog slow) apertures for some of the range than for none at all.