There are pros and cons to the appeals process.
On the minus side, it means an additional cost at what can be a very expensive time for any family. It may be disheartening and bring additional stress to the young person to go through an extended period of reassessment, without any positive change in the outcome.
On the plus side, the appeals process can help eliminate any doubts or recriminations about the exam result and help the young person move forward to the next stage of their lives. It also gives an opportunity to view good independent grading feedback on their work which is helpful.
The possibility of a downgrade (though rare enough) should also be born in mind.