Construct Classic had it and lots of people liked it. Also the built-in opacity setting is actually a multiply based on a single alpha value. If you extend the alpha value to a vector4 to cover RGBA then it's still one multiply and you get a tint effect too, so you kind of get it for free. This way it's also faster than using a tint effect.
Added effects always render after everything else - they operate on how the object looks without any effects, which includes things like opacity and the built-in color.