I want to know is it worth it?
Only you can answer this one after doing it yourself. There isn't a unanimous answer for this. It's a personal thing.
Temp-wise is the cost worth the additional 1100 bucks?
Custom liquid is a hobby and should be treated as such. If you pursue it for performance alone, prepare for disappointment.
Those that have jumped on board that boat and stayed have done so, because they end up enjoying it... just like my aquarium hobby of ~14 years, and still going.
Cost and performance are secondary - perhaps even irrelevant, to some.
The 3 most common things regarding custom liquid that turn away those that take an interest in it are:
Maintenance. Can't 'set-it-and-forget-it' and dust it out ever so often like you can with air and AIO/CLC. It's a bit more involved than those 2.
There's flushing the loop and leak testing, and some of the more showcase pastel coolants - if the user chooses to use those - can clog the loop up real quick, so maintenance needs to be done more frequently.
If the users uses distilled water instead of premixed coolant, they'll need to remember to use a biocide or killcoil.
Cost. Pretty self explanatory.
Research/planning - not doing enough of it, and running into problems(usually compatibility related, sometimes leaks are involved), making it even more costly than originally planned.
Lots of research and taking notes involved, which some people don't have the patience for; they want to get in and get started right now - that's a quick and easy way to get screwed...
I'm not trying to talk you out of taking an interest in custom liquid, but if you're considering pursuing this just for performance(which is a common goal of those that do take interest), don't.