400$ would be right (still overpriced a bit) if the 4 dives with boat charter were included. Course plus materials in most places I saw were around 200$. @OUBobCat all the dives in advanced training are introductory speciality dives - first of usually 2 to 4 dives. If you choose to pursue the speciality you did during advanced training instructor may skip the 1st one as you did it already. Doing only one dive at the advanced training doesn’t make you a specialist in any area.
Now to the main question - is it worth it or is it a cash grab? It’s a bit of both. If there is really challenging dive site some operators might as you for the deep dive speciality or at least to see the log to prove your experience. Wreck diver in my opinion is absolute the must, as you’re not allowed to penetrate the wreck without it (if you were than operator is irresponsible dick which puts money before your safety) and believe me that’s where the fun with wrecks begins.
No-one will ask you for UW photo speciality so you can make a pics, but you can learn a few tricks doing it. Most of the courses are like that, but wreck, cavern and deep specialities topped with rescue diver certification in my opinion are really the ones that’ll improve your knowledge and experience a lot and worth spending your money.