Hi:
Just to add another humble opinion for an interesting open question.
If you really like bikes and enjoy riding them, well... carry one and use it everytime you want or need. If you are not a liker... then don't.
Which bike? Whatever you like. Be sure to build/buy a nice and tough rack to hold it.
I have not made a single mile on my expedition truck yet (damn!) but I ride bikes on a daily basis. Love it. I cannot think of going anywhere without one hanging on the back of the truck, no matter if it takes one hour extra to go through customs.
Every overlander has his own opinion and experiences. Each one is valid. You should try your own hunch.
Greetings.
View attachment 505966
An early design of the bike/tire rack.