I have had KLM offer refreshment vouchers when flights have been delayed, but I think they only offer them once the delay is more than a certain number of hours - maybe your daughter's delay was below that limit.

I take it the connecting flight was on a separate ticket? On a through ticket KLM would have rebooked the onward sector. Travelling on separate tickets any onward connections are the passenger's responsibility. I would not travel on separate tickets without making sure that I have travel insurance which will cover missed connections.