Speed is a fine stat, but the problem with it in a game such as Sirilim is that it continues to scale as you move up in floors. No matter what you do, eventually enemies will outscale you in terms of speed - regular, nether, or demon, it doesn’t matter. Eventually, enemies WILL have more stats. Other games like Might and Magic solved the issue by assigning creatures speed that doesn’t grow with level. Slow creatures remain slow, while fast creatures remain fast in a comparable setting. Others use equipment/weight systems, or subsequent turns influenced by speed such that a quick creature can utilize more actions per time than a slow one. Sirilim just uses a classic, flat “you go, they go” model.
Moving first is such a massive advantage that it outright decides battles. From a player perspective, moving last can put the player in a situation where battle gets initiated and your team dies without the player ever being able to react. Facing Topaz Paragon puts the player in this exact scenario.
Topaz Paragon (the ability) also opens up the possibility for players to ignore speed entirely. You “sacrifice” two creatures’ artifact slot so your entire team moves first. Thus, speed no longer matters as the enemy will get its turn, then the player will have another.
In all, I think Speed is implemented poorly, and Topaz Paragon truly highlights it. Players go from one extreme (maximizing speed) in order to go first and climb floors to the other - outright ignoring it once Topaz Paragon on artifacts are located.