Only tested with macports: I may try to test it with Homebrew on a more modern (supported) version of Intel macOS in the future.
1. sacd-extract is available, but you will need to manually allow it to run in System Preferences → Security & Privacy
Only runs on Intel Macs at the moment (as I have no Apple Silicon Macs to test on).
2. CD Ripping works, pretty much as it does on non-Macs. However:
No comparison with AccurateRip is possible at the moment
CD Drive read offsets will be computed for you whenever it's possible -but if your CD drive is an Apple SuperDrive, it is not possible: they are made by multiple manufacturers, with different offsets, and Apple deliberately redacts the specific manufacturer, so no lookup of the AccurateRip drive offset database can be performed. It is suggested to use a non-Apple optical drive (these are identified sufficiently well to allow an AccurateRip lookup). You can also plug a SuperDrive into a Windows or Linux box, determine the read offset by running Semplice there and then manually set the discovered read offset into the persistent configuration file.
On Linux, the optical drive is polled continuously until the insertion of a CD is detected, then automatic identification and offset determination takes place. That is not how it works on macOS! On macOS, there has to be an audio CD inserted into the drive before you can tell Semplice to rip it. The operating system doesn't even enumerate optical drives until media is inserted into it, so there's nothing to poll to see if insertion has occurred!
It is strongly recommended to have only one optical drive connected to your Mac before attempting to rip: the code does not handle multiple drives at all well and errors will result if more than one drive exists.
Option 2 on the Ripping menu just does nothing on macOS: the drive detection mechanism used by that option is completely different on Linux vis-a-vis macOS, so none of it works.
3. Tagging works fine, including with custom tags. There remains a concern that foreign characters in names, titles etc. are not handled entirely correctly, but that may have been a one-off during early alpha testing.
4. Volume boosting works
5. Audio codec conversions work
6. Spectrum analysis works
7. SuperFlac creation and splitting works
8. Editing of embedded cuesheet works, but there is currently a hard dependency on WezTerm to display the text editor: macOS's version of xterm won't respect font size or font directives when launched and therefore you would end up with a ghastly, tiny text display that is functionally a disaster area. WezTerm is thus a hard dependency of Semplice on macOS.