With high Raw Power, you get jack-of-all-trade weapon that is good against everything. In my case, I started the game with Lance, and I have bunch of it with different elemental properties to used against the appropriate monsters. When I switch back to SA, I don't particularly want to grind LR or HR monsters for their materials. I want to jumped straight to the action, so I create Seregios SA that gives me high Raw with a monster on the same level as me to grind. Elemental damage deal higher damage to monster that weak with it, but if you don't have the luxury of money or time to grind, you might go Raw damage so you can used it just on everything.
As for the sharpness itself, it goes pretty well with Regios X set. That armor set gives Steady Hand, which have the effect of Mind's Eye plus Razor Sharp. The latter skill pretty much makes that sliver of purple sharpness last the same as any other weapon with natural purple sharpness. In the case of SA, the special properties of Seregios weapon of restoring sharpness by rolling works pretty well if you use sword mode a lot since the only way to traverse is by rolling. The only time my SA sharpness drops to blue is when the team is too good to the point the monster barely get up at all.
Regarding Seregios weapon special properties, this is why some weapon just don't work well with it. LS for example, will have its sharpness drop faster than I can restore them due to high rate of attack and the fact that I would most likely sheath my weapon for traversing the battlefield instead of rolling with weapon drawn because that's much faster and its drawn attack is much better at dealing damage to tails.
