I am certainly a proponent of divers reading more, and using other available resources, to gain knowledge and become better divers. Nor do I believe that PADI, SSI or who-ever is the final authority of diver training. Becoming a better diver is in my view a combination of taking training, building experience, and seeking knowledge from other divers and means available.
However, when it comes to any form of dive training that introduces the diver to new fields of knowledge (I'm not a self reliant instructor or diver, but I believe it sort of leans towards basic tech levels including use of redundant equipment, SAC, dive planning etc) I certainly recommend seeking a good instructor.
I know when I did my tech courses I learned more from my instructor's experience, and the various discussions I had in the class, than from just reading the book.
Secondly, of course local regulations and shop policies differ, but I think you make your own life easier having some kind of solo diving cert to show when you want to dive somewhere. Especially in a more 'tourist' dive destination, where due to the lower average skill levels of divers shops tend/need to be on the cautious side of things, and also being in the Caribbean with a lot of visitors from a country with a litigious culture.
I'd also check your insurances (travel/health/dive) for their coverage in case of solo diving, if some level of formal training or certification is required for coverage.
Last comment, please note this in the PADI manual provided in the link.
Therefore I don't think it is correct to share this manual in this way, without (presumably) permission or payment, and outside an official training.
Again, I'm not at all against divers educating themselves, neither am I a PADI 'fanboy' or of the business model of training agencies in general, but I feel the matter is slightly more nuanced than as per the previous poster.