CommentStreams:71544f4f37c50c58e0816ce8a323a29c

It's also a matter of considering the alternative--the only other thing to spend your effort on is making a variety of secondary decks. Ironically, this might have been more attractive before the changes: The cost of getting another deck to Level 25/high soulbind was small compared to what you had to sink in to get your main deck from level 25 to level 50, so not grinding out that last bit of power on your main deck might leave you enough to play with a few fun decks.

Now that the cost increase for leveling and upgrading stones is a bit more flat (and the cost of seducing to 5 stars is effectively quadrupled), you might as well just maximize your main deck. At the very least, it'll help you clear more of an event as Wanderer pointed out, and it'll probably save you some rubies if you're clearing all of the event artifacts. My primary account is maximized on levels and soulbind, while my original account is maxed on soulbinds, but only up to between level 25-40. That's a difference of less than couple thousand power, but my main account can consistently clear the guardian up to level 13-14 in five attacks or fewer, while the weaker account usually needs to use 6+ attacks starting at level 11 or 12. At that level, the difference in power is just about enough to let you survive an extra attack or two, and coupled with rage abilities that makes a huge difference in how much damage you do.