I have no problem with either short term trips or home missions.Short term can be an invaluable partner a long term strategy.
It can also be an extremely useful filter, enabling people to get enough experience to decide if they want to pursue missions.
(perhaps even more, it lets ministry leaders see the person in a high stress situation and whether they do well or not.) Home missions are just as necessary as foreign mission if every person on the planet is to be reached.
But we need to think of these things not as checkboxes for our mission involvement (“we did missions, we went in trips with our church”) absolving us if further responsibility, not as silver bullets for the missionary task.
Short term will see some converts, but if there is no route to discipleship the fruit can get lost.
Further short term can’t go where the nationality isn’t allowed; there are places and people in nations like Afghanistan, Pakistan, North Korea that some passport holders can’t get to.
And some nations (like India) are making it progressively harder to get in.
And just because a person is reached in America or England or wherever doesn’t mean they will successfully return home and disciples their family and friends.
To make a difference you need to commit to a people and a place for the long haul.
It may mean living there full time or repeated trips.
But regardless we need to commit to the places no one is trying to reach, and do whatever needs doing to reach them.