You're essentially paying a premium to have someone else install an OS for you - color me unimpressed.
And as far as QubesOS goes well it is still quite immature and has not received as much security scrutiny as say Linux. As some one who've used QubesOS for some times it's biggest downfall is the limitations of Xen in regards hardware utilization such as 3D acceleration.
QubeOS does not offer a share virtualized hardware layer which can support acceleration which means that things like 3D acceleration are done through passthrough(this to some extent is a limitation of Xen, and it's portrayed as a security feature in QOS).
Since it uses passthrough you can only assign a single AppVM to benefit from the acceleration and by default your physical GPU is assigned to Dom0 (it's actually a bit tricky to assign it to an AppVM). This leads to 3D acceleration being pretty much non existent in your actual applications and this is needed today for everything from browsing to even office use (MS Office 2013 and onward requires DX9/10 compatible GPU).
So in day to day use you end up having pretty much all of your activity either done in Dom0 or if you decide to tweak (which reduces performance considerably since your main desktop loses 3D acc.) your system in a a single AppVM which some what defeats the benefit of QOS.
And even if you have a multi GPU desktop any one who played around with multi-player single host gaming rigs using Xen and multiple GPU's knows just how much of a pain it is to do the passthrough properly, you have to ensure that the UEFI does not initializes the GPU's and once they are assigned to a guest that guest needs to be kept alive, you can't reassign those GPU's without a system reboot, and even suspending the guest might cause some issues as the GPU's are initialized.
QubesOS is great in concept but it's still a far cry from a usable general purpose OS and until they either decide to do proper hardware virtualization and reduce the amount of isolation between individual AppVM's or the hardware industry needs to build a new standard for shared passthrough (necro IRQ's!). Considering that passthrough is actually becoming more and more limited in the consumer space to prevent cheap personal computing parts from being used in the data center space I don't think that the latter very likely.
Qubes OS is very useable, as long as you don't need 3D acceleration. My solution to this is to have a seperate gaming PC that's completely untrusted.
The Qubes devs will not sacrifice the fundamental security properties of the system in the way you suggest to better service gamers.
Running YouTube at anything above 720p is difficult, 60fps isn't functional same goes for 1440/2160p.
Other applications like graphical applications, video editing, CAD etc are also non functional.
I don't know why have you brought up gaming I never did, but please don't even attempt to deny the fact that 3D acceleration is required for many many day to day use cases today that have nothing to do with gaming.
If you use MS Office for work, if you do any sort of content creation, and if you just want to enjoy HD media QubesOS is not for you and those aren't some edge cases.
Yes if you only use VIM ,Libre Doc's (And even Libre Office is using OpenCL these days for spreadsheets and many other things) and Gmail you can use QubesOS without any restrictions but if you need other thinks like for example even basic 3D modeling/slicing software for your 3D printer, Sketchup or Ligthroom well then sorry my dear.
So, all or nothing is wrong way to look at INFOSEC. I mean, if it's nation states, best to avoid computers in favor of trusted people, paper, and memory. ;) However, many methods provide a meaningful increase of security or just recoverability. Worth remembering.
This particular product: too much risk in it for me to say if it does. People are probably safer with OpenBSD or hardened Linux/BSD on high-end embedded board or old workstation.
Your complaints about lack of 3D acceleration seem to reflect your personal preferences, and are not an actual requirement for making use of MS Office or many other software packages. My six months of production level use provides simple proof by existence. There are some things - games included - that do need something like GPU passthrough, but your view of the situation is either outdated or simply wrong.