hello,

There is no high difference. TS intermediate syllabus will have chapter which may not be in NCERT but that is rarest. All the chapters and modules are there in both the syllabus.

Candidates mostly prefer NCERT because most of the non numerical questions are asked from NCERT book directly. Due to this you have to read the books line by line for PCM. for mathematics , chances for getting any subjective MCQ is rare but possibilities are still there.

This is the only sole reason. You can refer other books too for understanding concepts and getting the question bank to solve and practice questions.

Hope it helps!