Contrary to the memory of many players (including my own at times) it isn't very easy/common to do max damage with physical attacks. By the time you're hitting for 9999 with consistency you're incredibly powerful and very nearly near 99 (which is fun, but hilariously unnecessary to do in FFVI). Very few enemies that are worth mentioning (doubly so in the Advance version) are pussy enough to let you hit max damage, making that half damage handicap much more noticable.
Iirc this is true with most weapons, but I seem to remember it being possible to hit max damage with Ultima Weapon way before it is with most of the others. Which is another reason Ultima Weapon is badass.
Let's also not forget that, unless I'm hallucinating due to sleep deprivation, we should be comparing four hits of 6,000 to one hit of 9,999, or eight hits of 6,000 to two hits of 9,999. It's Offering that lowers attack, not Genji Glove. The fact that it halves the value of each individual attack doesn't nullify the fact that it gives you four attacks, so you should still be getting twice as much damage out of it. FF Wiki says as much, anyway:
The Master's Scroll relic (known as the Offering in the SNES version) allows the character to attack random targets four times, with half the attack power of a regular attack. Coupled with the Genji Glove relic, the user can attack eight times in succession.
So that should still lead to twice as much damage, or four times as much with Genji Glove, even if you haven't hit the damage cap with any individual attack yet. Though, yeah, the ones that ignore the damage penalty are probably the best ones to use before you've hit the damage cap. But, as it turns out, the Ultima Weapon is
one of these.
Also, as long as we're talking about the Master's Scroll:
There is a Master's Scroll Bug in the game concerning the Master's Scroll where certain weapons have special damage algorithms that ignore the damage reduction penalty. Additionally, there is a glitch involving using the Master's Scroll with the Mug command; after having Locke use Mug while equipped with the Master's Scroll (or any character using the Thief's Knife), the first item stolen will always be stolen, but any items that would be stolen afterward will not be added to the player's inventory (unless the monster is alone). Any items stolen after the first item cannot be stolen again under any circumstances, meaning that some items, such as Ultima Weapon's Ribbon, are lost.
I almost never use Capture/Mug anyway. Too much risk of killing the enemy before you Steal successfully.
Ultima Weapon isn't a bad weapon, especially due to it's defense ignoring properties, but its relatively low intrisic attack power prevents it from being god tier. I would say it's a good fit for Locke, but the UW's damage mechanics are mutually exclusive with the Valiant Knife, and the VK at low HP is fundamentally a more powerful weapon than UK at high HP.
I almost never use the Valiant Knife due to the fact that I dislike keeping my characters at low HP. If that fits your play style, then yeah, it can steamroll most of the opposition.
It's for the same reason that I haven't seen any of the Desperation Attacks in normal gameplay. If at all possible, I heal my characters when they're at critical.
I wouldn't call it useless. Ultima has enough of a prohibitive MP cost that you'll need to replenish your stock after a few turns, and why waste a turn casting Osmose if that turn instead can be used to cast another Ultima? It does so much damage (usually max) that another turn casting it instead of casting Osmose (or using an X Ether) can really matter. Osmose is a great spell, don't get me wrong, though. You can however make a great argument for replacing the Celestriad with a Ribbon however.
This is true in boss fights, but in the majority of the game I don't think it's really that important. Most of the random encounters aren't that powerful that they can wipe you out in a single turn. Indeed, most of the enemies will be wiped out by that Ultima. And by that stage in the game, really, you should be able to have more than one person able to cast Ultima, which means that when you're using Osmose with one character, you'll be able to follow it up with an Ultima from another.
(or it seems that all the other paths are either blocked or collapsed and you can't escape the random battles.)
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