Why does Tasker need so many permissions ?
Because it can do so much!
Unfortunately, Android requires that an app specify it's permissions even if they are
never used, which means that permissions for all of the things which the user could
potentially ask Tasker to do need to be specified.
If you are still concerned, consider that Tasker has over 25,000 downloads at the time of writing and any abuse taking place would quickly be discovered.
As a convenience, the Exit task with such profiles is replaced by an extra Enter task in case
you have a lot to do with that profile.
Note that the tasks you specify execute in the order they are specified, their actions
do not alternate.