It is not. Puberty blockers just slow puberty. Exactly what it says in the name. When you stop taking them puberty resumes as normal. You could even continue hormone therapy without surgery, but ya'll like making shit up in your head. Top and bottom surgery all require rigorous sessions with a therapist, lots of money and even physicals to make sure you're physically stable enough to have said procedures, legally. Medically transitioning is a fucking rigorous ass process. In short, a person on puberty blockers or hormones can decide against surgical transition and continue hormones.