That's a good question. In fact, this is quite a lively debate between the international community and UN agencies present in Bogota. The government is absolutely certain that it's best to treat the Venezuelans as migrants who are eligible for two-year residency, in which time they can work. It's important to bear in mind that to enter Colombia from Venezuela, all they need is to put their identity details into a website run by the Colombian government, print out a document from that and they can get in without a passport or without even a valid identity card.
The problem is, what happens at two years? Will those working residency visas or cards be renewed? There is an uncertain future. The refugee approach, which, as you've said, can be based more on camps is often based on systems of protection with no automatic right to work. It is one that will be much more costly for the Colombian government, which is the reason why it was reluctant to take it, but it would, perhaps, offer a greater degree of certainty over the horizon.
I think what makes the Colombian—