You said it yourself: you had spent a lot of time learning the patterns, but had grown frustrated by that time. Basically you’d have two choices

• what you did, and finish the fight easily using summons (which is easy only because you already spent a lot of time learning the boss)
• decide to do it without summon, and maybe have the satisfaction to win without help, or submit yourself to too much frustration, rendering the victory meaningless because at the end it had become a chore, and not fun at all.

At the end of the day, the most important element is to have fun. But even with summons, victory is never underserved, those games are still brutal.