The point is that missions is a large team effort, and there is a need somewhere for just about any kind of giftedness. Often we don’t know beforehand, or are outright mistaken, about how God will use us. So, if you look in the mirror and think, “How could I possibly be of use to God overseas?”, don’t give up hope. There is an even more important question here.
We see needs and what we can do to meet them, and we step forward and are used by God to bring blessing. The real question to be asking is “How am I being used by God to bless others?” That is often the best indication of both the type of gifting one has, and the state of one’s heart in service.
A servant’s heart doesn’t magically arise when one is plunked down overseas. The degree to which you are pouring yourself out for others now is probably the best indication of how you would be elsewhere. And, in considering fitness for missionary life, it probably doesn’t matter so much whether one is doing this versus that, so much as whether one is doing it serving the Lord and others.