However, the single pilot, non bus driver, can be presented with unforeseen situations that lead to distraction (usually multiple) at the critical moments.
I know that some people tend toward such last chance warning systems, and if such systems work for those people, who am I to knock them. But for me, and the GA pilots I train, no "save your butt" systems beyond those in the aircraft type design. You save your own butt, by diligent configuration assurance of the aircraft at the appropriate times.
I've flown with pilots who have adorned their aircraft with all manner of gear advisories, AoA systems, and enough avionics to slow the alternator. Such supplementary systems are often the source of the distraction that they are supposed to prevent. And worse when there are layers of them.
What is regularly missed during STC'd system installation, are those really important words on the bottom every STC certificate. They say more or less, the installer is responsible to assure that there is no unfavourable characteristic resulting from the interaction of that and other STC'd mods which might be on the aircraft. Gear warning systems could enter this area, as their introduction could affect human factors, or their latent failure could create risks associated with misplaced dependance.
Or, you have a bare bones RG aircraft, and you know it's
all on you.
You configure the aircraft properly, or
you suffer the consequences. It's kinda like contacts lists in your phone, who remembers phone numbers any more? I nearly never use contact lists or speed dial, I dial by hand every time, and I remember most numbers. I operate my landing gear by hand, I speak the position words aloud, and I remember to do it next time. So far, so good.
Like parachutes on Cirrus', some pilots will not be dissuaded, and that's their privilege. But, you asked the question, and my personal preference is as few systems as are needed to safely operate the plane. Nothing added which is not vital.