Why it works
What individual pages do differently
When every participant has their own page, three things change.
First, the ask becomes personal. "Please sponsor Jack for his fun run" is a specific person doing a specific thing for a specific reason. Supporters give to people, not to general pots. Anyone who has ignored a generic charity envelope and then sponsored their colleague's nephew without thinking has felt this in themselves.
Second, the ask travels. Jack's parents share his page in the family group chat. The grandparents sponsor. Someone posts it on Facebook. A colleague sees it and sponsors. A single page can quietly reach people the event organisers will never meet, and the supporters most willing to give to Jack are often not at the school gate.
Third, the maths becomes visible. When every participant has a page, the running total accumulates in public. Participants check it. Parents check it. That visibility creates a small but real social pressure that paper forms and shared donation pages don't. Pages with a few sponsorships on them attract more sponsorships.
None of this is theoretical. It is the difference between asking once and being shared a hundred times.