Thanks for your replies. You've all, and irishguy28 in particular, captured where my discomfort comes from.

A few more words about my situation: I was helping a relative whose plans have changed. They had a flex ticket for a Europe-Asia roundtrip in a distant future, and they wanted to change both the date and the departing city for the return flight. They thought it was more natural to change rather than cancel their ticket, and that's when I started to compare both approaches. I must say the AFKL website is a bit misleading, as the "manage my booking" page contains some vague wording which suggests that cancelling might be complicated and the refund might not be guaranteed. At least that's how my relative read it, and I had to read again the initial ticket conditions before reassuring them. Those who do not read FT can have a dangerous life sometimes.