J2F I have to make good decisions on what feature to add and what feature not to add.
There are hundreds of fitness tracker/services out there. If I add Garmin support, the next user is asking for Samsung Health. When I add that, next one is asking for Huawei Health and so on... And every user is disappointed if his integration is not there. I mean, other journaling apps don't have that kind of feature at all.
Of course it would be great to support all of them but it's not like that I just check a checkbox and the integration works. It's a lot of work behind the scenes, every Fitness API works differently and the process to be allowed to access health/fitness information of Diarium users sometimes is very tedious. Last but not least, when I add an integration I also want to commit myself to support it for a certain amount of time. Fitness services change their APIs, data, names, logos, requirements and I have to adapt every time when such a change occurs, which costs a lot of time.