When compatible hardware is available, it’s expected that having packages built for RVA23 will have a big impact on performance. You can already see a big part of that with the vector (V) extension: running programs built without it is akin to using x86 programs without SSE or AVX. RVA23 is the first RVA profile that considers V mandatory rather than optional.

You might see a similar performance impact if you target something like RVA22+V instead of RVA23, but as far as I know the only hardware systems that’d benefit from that are the Spacemit ones (OPi RV2, BPI-F3, Jupiter) while that’d still leave behind VisionFive 2, Pioneer, P550/Megrez, and even an upcoming processor UltraRISC announced recently. The profiles aren’t exactly intended to be used for those kinds of fine-tuned combinations and it’s possible some of the other RVA23 extensions (Zvbb, Zicond, etc.) might have a substantial impact too.

Hardware vendors want to showcase their system having the best performance it can, so I expect Ubuntu’s aim is to have RVA23 builds ready before RVA23 hardware so that they’ll be the distro of choice for future hardware, even if that means abandoning all existing RISC-V users. imo it would’ve been better to maintain separate builds for RV64GC and RVA23 but I guess they just don’t care enough about existing RISC-V users to maintain two builds.

The parent comment mentions working on security for a paid OS, so looking at the perspective of something like the users of RHEL and SUSE: supply chain “paranoia” absolutely does matter a lot to enterprise users, many of which are bound by contract to specific security standards (especially when governments are involved). I noted that concerns at that level are rather meaningless to home users.

On a personal system, people generally do whatever they need to in order to get the software they want. Those things I listed are very common options for installing software outside of your distro’s repos, and all of them offer less inherent vetting than Flathub while also tampering with your system more substantially. Though most of them at least use system libraries.

they added “bash scripts you find online”, which are only a problem if you don’t look them over or cannot understand them

I would honestly expect that the vast majority of people who see installation steps including curl [...] | sh (so common that even reputable projects like cargo/rust recommend it) simply run the command as-is without checking the downloaded script, and likewise do the same even if it’s sudo sh. That can still be more or less fine if you trust the vendor/host, its SSL certificate, and your ability to type/copy the domain without error. Even if you look at the script, that might not get you far if it happens to be a self-extracting one unless you also check its payload.

A few reasons security people can have to hesitate on Flatpak:

• In comparison to sticking with strictly vetted repos from the big distros like Debian, RHEL, etc., using Flathub and other sources means normalizing installing software that isn’t so strongly vetted. Flathub does at least have a review process but it’s by necessity fairly lax.
• Bundling libraries with an application means you can still be vulnerable to an exploit in some library, even if your OS vendor has already rolled out the fix, because of using Flatpak software that still loads the vulnerable version. The freedesktop runtimes at least help limit the scope of this issue but don’t eliminate it.
• The sandboxing isn’t as secure as many users might expect, which can further encourage installing untrusted software.

By a typical home user’s perspective this probably seems like nothing; in terms of security you’re still usually better off with Flatpak than installing random AUR packages, adding random PPA repos, using AppImage programs, installing a bunch of Steam games, blindly building an unfamiliar project you cloned from github, or running bash scripts you find online. But in many contexts none of that is acceptable.