I found that if I map FN to the Caps Lock key (like on my Pok3rs and Nano 75s) and chord it with IJKL for arrows, I am quicker than when I use arrows on the nav cluster. And since IJKL are home position keys, I believe FN+IJKL would also be quicker than if dedicated arrows were on the bottom row. That's why I prefer 60% boards over TKLs; especially since I (only) use 60% boards with my iPads where a numpad isn't needed, and a TKL would just be way too big.
Honestly, TKLs are probably the most useless format for me, second only to 40% boards (or anything smaller than a proper 60% board, really).
If it works for you, great.
However SpaceFN (for example) has the same kind of advantage, with the added benefit of not requiring your left hand to do anything. So the left hand is free to do all the usual "chords" we use all the time when editing text: Shift-arrow (select), Ctrl-arrow (move word by word), even Fn-Shift-arrow (select to begining or end of line)...
Still, I notice that in long coding sessions I often spend a lot of time reading code before making changes. When I do, I don't want to have to keep both hands on the keyboard. I need to relax on my chair because I suffer from lower back pain. In this case, having to keep my left hand on CapsLock or any other key located on the left hand side would be really inconvenient.
Mind you, even having to keep space pressed (when using SpaceFN) becomes tiring after a while. I think it also has to do with having to keep your hand floating in the middle of the keyboard. Resting your wrist on the desktop is possible when you are hovering above IJKL, but it is easier with arrow keys located in the bottom right.
I think the arrow keys are essential keys on a computer keyboard. I see that people want to convince themselves that they are not primary, essential, first class keys.
I have been one of those people. But the arrow keys are actually more important than, say, letter keys. After all, if you spend time editing text on a computer, you are using the arrow keys more often than any letter key (I have done stats on this). Your computer keyboard has alphabetical characters, because you type these characters all the time, so it must also have arrows because you use them even more.
Limiting the keyboard to the classic typewriter rectangular alphabetical block (what you get on a typical 60% keyboard like the GH60 or the Poker) is a relic of the past. It's obsolete. The HHKB is the perfect example of this trend, as its shape is even closer to the one of a 1930 typewriter keyboard. I suspect it's part of the appeal, unconsciously. I have an HHKB, and I love the look too.
We are not using typewriters, we are using computers, and on computers the arrow keys are used so often that it does not make sense to not have them directly accessible.
I love the FC660 (C or M) because it breaks the rectangle and adds an extension for the arrow keys. Some people don't find it pleasing, visually, but remember that your hands do not see. My hands find the arrow keys easily because they are a little bit outside the rectangle. I own four FC660, the last one, that I purchased in June, is this one:
https://www.amazon.com/LEOPOLD-compact-keyboard-English-FC660C/dp/B00PINUGJOFor those who absolutely want a rectangle, there are keyboard designs that include the arrows in it. For example this one, that I have just noticed. I think it's a recent one, and I think it's programmable. I think Vortex nailed the (almost) 60% this time, and I'm actually tempted to order one:
https://mechanicalkeyboards.com/shop/index.php?l=product_detail&p=4164Or this one, with a design that has been around for a while:
https://mechanicalkeyboards.com/shop/index.php?l=product_detail&p=3917I'm not trying to convince you, because you seem to be satisfied with your setup. But for those who are hesitant about purchasing a 60% keyboard without arrow keys, they should know that there are good-looking alternative
with arrow keys.