Because you know what makes customers want to come back? Making them see you as part of the reason they have things to celebrate.
Somewhere along the way client experience became all about building portals, automation and throwing in a private community. But CX is more than that. (I know so cheesy).
CX is a feeling. A vibe. A sensation. The thoughts your clients will have when they're interacting with your brand.
It's the difference between someone signing a 6-month contract instead of 3-month, the reason businesses are chosen over and over again even if with higher prices, and the real reason clients are going to bring their friends.
Think about it - why do tiers with live support cost more, why are you less stressed taking the flight that gives free drinks, why do you login to the communities you love to engage with?
Two words - client experience.
Also, it's not really about the birthday it's about making people feel special and creating spaces for celebration.