When debating Regulation 261 the Parliament/Commission/Council agreed that the compensation for CANCELLATIONS should be punitive - This was because of the belief that airlines cancelled flights primarily for financial reasons and they should be discouraged from doing so.
The same groups agreed that DELAYS should not be compensated. Many reasons given but (IMHO) the most important was they did not want to encourage airlines to operate in unsafe conditions (or have crew pressured to do so). They also saw a cancellation as being worse than a delay - seeing as the passenger actually travelled.
That's the way the Regulation is written, and if read the text you will find nothing about delays being compensated. The duty of care, meals; phone calls; hotac; etc do apply in cases of delays. Also the provisions on delays are all in relation to delay in departure, not delay in arrival.
The European Courts did not like that delays were handled differently than cancellations concluding that a delay
could be as bad as a cancellation. Subsequent rulings have 'interpreted' the Regulation in that a delay of more than 3 hours
could be as bad as a delay, but the exclusions due to extraordinary circumstances (which applied to cancellations) also applied to delays.
The media has interpreted these rulings as meaning that
every delay of more than 3 hours
must be compensated. And something considered extraordinary, for example airport closures; bird strikes; technical faults; fuel contamination; etc would only apply to that flight and not to subsequent flights of that aircraft.
The OP's daughter probably paid something between €45 and €100 for her ticket while is entitled to €250 in 'compensation'. If the aircraft was full Easy would have revenues of €7,155 to €15, 900 plus on board sales of (a guess) of €800~€1600. Add to that the fees and the total revenues would likely still be less than €20,000. (These are revenues not profits.)
And the Compensation as decided by the European Courts? €39,750 if the flight was full.
Oh, and if it had been a rail journey? Well according to Regulation (EC) No 1371/2007 of the European Parliament and of the Council of 23 October 2007 on rail passengers’ rights and obligations.
Delays and cancellations
This Regulation strengthens passengers’ rights to compensation in the case of delays or cancellations. Passengers may claim a minimum compensation equivalent to:
25 % of the ticket price for a delay of 60 to 119 minutes;
50 % of the ticket price for a delay of 120 minutes or more.
So if this applied to air the OP's daughter would get something between €23 and €50. The entire aircraft would be entitled to something between €3,600 and €8,000.
Oh, remember the compensation amounts was supposed to be punitive to change the behaviour of airlines cancelling flights for economic reasons? Well, a study done by an outside party for the EC showed that there was no measurable change to the rate of cancellations of European airlines. The study was posted on the EC's web-site, but has long disappeared.