Alright explanation for height being a scale value, so please bear the long post. (A lot of these are assumptions, so feel free to correct if you see fit
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When you're working with 3D models, in addition to height you have to work with other two dimensions which are width and length (basically an x, y, and a z axis) that at least to my understanding don't appear to be in the data. So when you develop a 3D model your work area is basically a cube with set values, and the height value seems to be the measure they decided to use to scale and determine the characters correct size during the game.
In a game like smash, all the models are worked in a cube of determined dimensions and the character models are developed within the boundaries of the cube. Now working in this area of this set size would leave some interesting results if you compare models directly, small characters end up really big and big characters end up being hilariously small. So when you need to put the characters in game, you need to increase the scale of the bigger characters more than you need to increase the smaller ones so that every character appears on scale.
When you're working in this space restrictions with the addition of width and length, you need to fit characters within the cube. Some characters end up becoming even smaller like Bowser which is also one of the widest and lengthiest characters so you need to increase the scale even more than with other characters of similar size.
Now, there are a few discrepancies with some of the characters height values which ends up making explanations a bit more difficult. Ridley would need to have a higher value than samus and they have the same one, which could potentially mean that he was developed in conjunction to Samus and used an area twice as tall. (This one is practically a supposition).
Why all of this is important, while the character can be Lucas/Ness size it doesn't necessarily mean so. It only indicates that the model has been increased a certain number of times, and it could be an even smaller character that needs to be increased more due to being wide or it could be a bigger character that doesn't need to be scaled as much. This method I'm explaining is relatively easier to develop rather than working with the dimensions directly as you can change the values and play with the measures as you see fit, also this explains the slight discrepancies in height of characters with the same "height".
Based on these principles, to give an example we can use 2D images. For this lets take these images of a mouse and a cat which are the same scale:
In these the cat looks smaller than the mouse despite the pictures being the same size, but when you need to put them together and to scale you need to increment the cat size a few times(both height and width) before they are in correct scale one with another. Now if you add a dog to the picture
The dog would need to be increased as well, and would end up being a few scales bigger than the cat.
So basically thats it class, hope this explanation is understandable enough about the value.