Short answer
Choose flip when the business plan is to sell after works. Choose long-term hold when the plan is to keep the asset and judge it through income, refinancing and future exit value.
How it works in Koreograph
The exit strategy controls which assumptions are most relevant. A flip focuses on sale value, selling costs, finance during works, tax at exit and time to sale. A hold focuses on rent, voids, operating costs, refinance, debt cover and long-term wealth.
Developer view
If either strategy could work, model both as scenarios. The right answer often depends on whether the asset creates enough rent cover to justify holding or enough margin to justify selling.