you should not do USMLE World offline for the following reasons:
1) It's outdated and they have changed many of the questions.
2) It's illegal and considered a crime in the United States which is the country where you want to build your future in.
3) It has no means of assessing your performance and it does not compare you to other UW takers.
4) It will ruin you online USMLE World as many concepts are repeated but in a different style and so this renders your practice invalid.
5) You cannot do timed blocks and this is very important to have adequate practice for the exam.
6) You cannot do subject-wise questions and so you miss the opportunity of hitting on your weak subjects.