Even though Cloud, Ex-SOLDIER offers additional card draw for each equipped creature, it still ends up being far better to just focus on piling everything on Cloud and protecting him rather than spreading it out: you'll kill people faster with commander damage, you'll reap bigger rewards off stuff like Behemoth Sledge gaining you way more life, and it's simply easier to protect a single creature than trying to protect your entire board
The drawback is very obvious: Once your O-Card gets destroyed, your opponent gets back, which was lost
If youre forever wishing you could sneak just one more card off the top of your library each turn, this might be a solid choice
Trading it off after ramping is an easy 2-for-1, but if you dont you can still collect your 2-for-1 anyways with chapter III
Seeing as Summons in the actual Final Fantasy franchise only stick around for a few turns, having them represented as Sagas in Magic makes perfect sense