Is it permissible to shorten and combine prayers during a permissible journey for worldly matters, or is that restricted to journeys of obedience?

If the travel is for a permissible purpose, there is no harm in taking advantage of the concessions of travel, such as shortening prayers and breaking the fast. However, if you intend to stay more than three days in the country you are traveling to, you take on the ruling of a resident, meaning you complete your prayers and do not break your fast in Ramadan (definition). But if the stay is three days or less, you may avail yourself of the concessions. This is the view of the majority of scholars, and it is the more cautious approach.