I respectfully disagree. Its ability to be installed on a variety of hardware platforms is one of its strengths. If one’s requirements outstrip the processing power of, for example, an RPI3, Home Assistant OS can be installed on a more capable machine (perhaps an Intel NUC).
Compare that to other available home automation “appliances” that are constrained to a single hardware platform. If you exceed the platform’s abilities, you have no option to upgrade other than buy another device and divide your automations between the two (and live with the additional complexity of this arrangement).
The Home Assistant OS installation method is designed to be installed on an SD card. Installation on an SSD is possible but by means of community-provided instructions. If neither an SD card nor jury-rigging it for SSD is acceptable to you, then the remaining three installation methods all assume you are familiar with Linux (and Docker). If you are not familiar with Linux, then you will have to learn, and if you don’t want to learn then Home Assistant OS is your only viable option, or an entirely different product.
EDIT
Have a look at the documentation for openHAB’s installation. It describes how to install it on:
- Linux
- Windows
- macOS
- openHABian
- Raspberry Pi
- Armbian
- Docker
- Synology DiskStation
- QNAP NAS
All assume you know something about the underlying operating system (which happens to be Linux for most of its listed installation methods).