The count that stays current until the oven heats
Dinner parties are the event where a wrong number hurts most. Six people, and a hidden plus-one wrecks the table plan. Sixty, and a missed allergy is an emergency rather than an inconvenience. What a chat-message invitation cannot do is keep track: Marta said yes in March, changed her mind in May, and the message that says so is buried under a holiday photo.
An event page keeps the number honest until the last hour. Every reply that arrives shows on a live list, guests who have not answered are visible as a gap, and WhatsApp or email reminders go out to them so you are not setting place cards against ghosts.