The host gets to attend their own party
The traditional trade-off at a hosted celebration is that somebody organises the entertainment and therefore experiences the party as staff. Everything here is set up in advance and requires, at most, one announcement and one winner read out. That is a materially different evening for whoever is hosting.
It works on a mixed guest list, which is the hard case
Most party entertainment implicitly assumes a homogeneous room. A quiz sourced from three different stages of someone's life doesn't — the childhood questions belong to the family, the recent ones to the colleagues, and neither group can win alone. That structure is doing real social work.
Milestone birthdays are archive events
A 50th is one of the few occasions where a person's entire history is represented in one room. The photographs that exist of that are scattered across every guest's phone and a few shoeboxes. Collecting them in one place, once, on the night it's easiest to ask, is worth more than the party itself in the long run.
Nobody has to be picked, called up, or embarrassed
The reason adults dread organised party games is the risk of exposure. Everything here is played from a phone, in a seat, at whatever level of engagement each guest chooses. The people who want to compete compete; the people who want to watch watch. Both are participating.
It scales down to a living room
None of this requires a hired venue, a DJ or an AV budget. A TV, a speaker and a printed QR code on the fridge is a complete setup for a party of thirty.