Ok no worries, that will be added!
I have a product vision, I try to think about the end user more than the developer 
The advantage of having units fixed in the product is that we control the display in Gladys:
- Units can be displayed in a short form « 3h » and in a long form « 3 heures » depending on where in the interface
- Units can be auto-converted so they’re readable (Wh → kWh), or to respect the user’s preferences (°C → °F)
- Units are translated. If you have a foreign friend at your place, a foreign woman (or if you just want to show your instance on the internet), the units will be displayed in the language selected for the logged-in user’s account. « partie par million » in French becomes « Parts per million » in English.
None of that is possible with units entered manually in Gladys.
I created a small GitHub issue so I wouldn’t forget:
So I’m closing this topic then!