100%, I'm following a similar approach to you with yet another notes app solely for my own use.
Have you written more about your personal project anywhere?
One thing I only realised once I started building my own tools, is that you become - from day one - an unmatched world-class expert in using that tool. This seems obvious and inconsequential on the face of it, but how many pieces of software do you use where you can say with 100% certainty that you know every single thing about it?
Every feature, every shortcut, how it all works internally...
It's only when you use something self-crafted that you realise what this actually means. If it's a tool that you use for work or productivity - you can become exceptionally productive with it due to this from-day-one "total mastery".
This compounds if you iterate. Using the tool daily and feeding back in little fixes and optimisations as you go. The tool grows with you and molds to your use of it over time.
It's obvious that the tool is going to be well suited to your needs if you built it - but it was less obvious to me ahead of time what benefits the side effect of "total mastery" would also bring.
For me, my notes app is now used as my personal knowledge base, project management tool, todo list, daily planning tool and for journalling. Because I built it, I'm extremely effective at using it - and it's lean and fast - only with the features that I know I need.
In addition to being a very fulfilling project - it has created a degree of leverage and efficiency that I didn't expect!
My conclusion is that we should all experiment more with creating our own tools.