I only use it IF I have a link pin that chronically loosens. That is extremely rare with my modern Rolex watches. The threads are so close and precise that if properly finger torqued, they never move for me. I always do a visual and finger feel down the bracelet and if I ever catch a pin moving I then apply purple loctite. Now be warned with the Jubilee link pins as if the get very stubborn and stuck, they can be extremely difficult to remove even with heat without mowing the head of the pin. I have seen this with a BLRO jubilee link pin from the factory. I had all the right tools and procedures, and I barely got out without damaging the head and I have done hundreds of bracelet adjustments over the decades.
This is why I am hesitant to openly recommend using Loctite in every case. Most bracelets won’t need it.