Thanks for your questions.
I see Exshome as an application that allows to automate some home actions. Its architecture focuses on the automation.
Let me tell you a history behind this project:
TLDR, project history
We wanted to listen to a music in our office back in 2018. I have removed the dust from Orange PI Prime and connected it to an audio system. There were some music player solutions, but they required user interaction to start playback. Another ones had other limitations or felt too complicated for my purpose.
I have spend my weekend to create a simple CLI player on top of mpg123. It picks a random file from folder and plays it. It exits on the file end. This script also generates simple “status” file, and accepts user input via some dark bash magic 
I have used systemd
as a supervisor, so it started the script on system startup and restarted it when the file ended.
This solution was extended with cloud commander, so people were able to upload their tracks.
Repeating tracks were not the best thing to listen to, so we have decided to listen to a neutral radio on workdays and launch our tracks on holidays, to make them feel special.
This led to another systemd
template together with a stripped bash player script.
The team asked for YouTube tracks and playlists, because it is more fun to see the playlist contributors. It became more easy to find who to blame for ugly track in the playlist 
This led to a local_assistant thing. I have made it public today too 
It is a Phoenix Live View application using Mopidy (together with Mopidy-YouTube) as a backend. It was fun to create it, and it was a prototype for Exshome. It is far from perfect, but it works well for a couple of years already.
I liked the results and wanted to make it something more than just a player. The architecture of local_assistant
does not allow extend and test it easily. We have also had some stability issues with Mopidy Youtube integration over this time. My Mopidy client was synchronous and polled the server too hard every second, instead of subscribing to the changes.
That’s why I have decided to create another version of application, together with another player backend. Exshome uses MPV, and its client is much more tolerant to the server 
We have had some routine player tasks at the office: someone needed to start it at the start of a working day, shut it down in the evening, so neighbours can sleep nicely and turn on our special Friday or Christmas Playlist and have a party 
Sometimes previous players lacked observability. If they refused to play a track, I needed to dig into their logs to find out outdated youtube_dl
version, or deal with some network issue, etc. Exshome already has many features to deal with this issue. It is easy to attach to get output of running MPV application, its state, every message, etc. There is no UI for it right now.
Now project has building blocks for applications and two of apps: Clock and Player. Both are very simple, but they are enough for me. I plan to start implementation of Automation app. It will be responsible for bringing more “smart-homeness” into the project 
I also have an Arduino kit full of sensors, and actuators in front of me. It gathers the dust and demands for a real work. All I can do now is just tell it to wait for a brighter future 
I can not compare exshome to home-assistant, or openhab. They are way more mature. Thanks for the link and your suggestion. I can use these solutions as inspiration.
I plan to attach low-level things (like Arduino) to Exshome and automate everyday’s life with it. So it will be more DIY thing, than buying a ready-made hub from smart home provider and attaching ready-made locks, sensors and equipment via Z-Wave to it. Possibly the project will have these integrations someday. I will be happy if it help someone to release own creativity.
The project is full of Elixir code and tests. I like hacking it and hope that someone can find it useful too 
Conclusion: the project is in early stage now and it looks more like a feature-less player (which can fail if there is no MPV installed) and a clock. It dreams to become Smart Home solution one day, but now it has only Smart Home as a part of its title.
Plan to post updates about its state in this thread 