SSR grail's 400 points (or, 40 points by your scale), compared to the standard SSR's 350 points. So correct, it is never a good idea to expend eyes for the SSR grail. Especially when the most points you'll ever need for a skill level up is 580 (SSR lv 29->30). As well as the fact that replicating those points through f2p ways isn't exactly hard.