Many people need to use an inhaler (or some other kind of medical device) a few times per year, on SOS. But when was the last time you did?
It is very important that you should know when it was the last time you used such a device, and how frequently you do it. Trusting your own memory isn't reliable, and if you keep track on some notepad, it's easy to forget, and potentially hard to always do the calculations.
There are a few apps that help you track and remind you of such events, but those apps also record all that data and use it to sell you more stuff, or simply sell it to other companies, so those can sell you more stuff.
Loggit isn't like that. You own your data and only you have access to it. It's only on your device, and if you want to synchronize it across devices, you can set up your own server for it. The database synchronization engine is open source (CouchDB/PouchDB) .
It's also much simpler, and that puts you in control of what you should do with your data.