Melee training mode combos can be much more creative and better than actual match combos... :
http://www.youtube.com/watch?v=IebG0RZ_PeY&feature=related
Try to see any Yoshi player do a combo better than that in a real match.
I think the main thing being mis-understood here is that training mode combos, actual match combos, and tas combos are three completely different things. Sure, in terms of actual use in a match, it is actual match > training mode > tas (since tas is usually impossible for a normal human to do), but in terms of style, creativity, and basically every other category, it's (for the most part) tas > training mode > actual match.
http://www.youtube.com/watch?v=JmygXu1woww
is this combo bad because humans will not be able to recreate it? It's a different type of combo.
Well... I've said the same one line point and repeated it like 10 times already... so I guess I'll end my post here before I make my post too repetitive...