The main difference is the amount of information you enter when uploading an activity. When you select the option “this activity can be booked separately”, you will have to add the pricing, availability and the booking and cancellation policies.
While activities are not shown as individual products in the front-end at the moment, adding the pricing at this stage can make sense in order to have it transferred to the pricing inside a package, i.e. the pricing of the activity will already be added to the pricing of the package.
NOTE: The pricing of an activity will only be copied to the prcing inside a package if the seasonality overlaps. If you apply a different seasonality to a package than to an activity itself, you will have to re-enter prices inside the package form.
Usually we recommend selecting the second option “This activity is always part of a package”. This allows you to quickly upload activities and have them ready to be added to your packages.