I would say that the only difference is when you are working in a bigger team and there is a big change in design or something like that. As a team leader you may prefer to separate page templates from LiveView logic. It’s easier to track changes made only in the logic or template if they are separated.
This has nothing to do with components and live components as they are supposed to be used on multiple pages. Therefore only pages should have templates in separate .heex files, so you can search using git for a specific type of changes simply by logging all .heex or .ex files.
Of course as said technically there is no big difference and therefore people especially in their own projects are fully free to pick their favourite solution. The bet things in Phoenix is that it’s technically a library and not a framework as there is not much stuff required by some convention and developers have lots of flexibility in how they prefer to organise their code.
However for me if there is specific reason for adding .heex files even if it’s limited to very specific cases and there is no specific cases for the opposite way then I prefer to “standardise” it and simply do so in all my projects. After all even I can’t say how big team may be working on the pet project I’m working on right now. It’s especially better since once decision is made it doesn’t take any extra time and I don’t lose further time on investigating “what I prefer” for every project.
The only exception here are scripts, but scripts have their own rules. Obviously a small script is preferred to have a single file source, so they usually don’t use .heex files. As said scripts are not projects, so they live on their own rules.
For me that’s all and I never saw .heex files as introducing any kind of “:discomfort”. I believe it’s rather a personal perspective i.e. how you are used to work with templates. This is the only thing that can introduce a “discomfort” as we simply do the usual thing in a way we are not used to. I would say that the “discomfort” feeling is often wrongly taken.
People should try various things and see on themselves what work for them. Everyone should create their own standards based on nothing else than a practice. If a feeling is not based on it then it often turns into a false assumptions which depending on person may be hard to figure out, admin and/or change in future.
