The reason Aizen left 8,000 task Wisdom points in reserve wasn't just because of the newly opened Wisdom Shop, which could potentially offer rare and powerful items that required a hefty exchange. It was also because, now that he had become an outer Clan disciple, he had access to the Sorcery arts techniques of the Heaven Demon Clan's outer Clan. Having a reserve of Wisdom points would allow him to quickly learn or acquire any techniques he deemed useful.
The six medium-level Wisdom treasure chests he had acquired were a precious opportunity. Especially with his privilege of specifying one item to maximize the value of the chests, he could make sure he chose wisely. As the chests shimmered in his mind, Aizen methodically inspected each one, his eyes narrowing as he considered his options.