I admit that this is based on my own observation and participation in user forums, but when markdown apps offer a choice of source mode (which shows the markdown codes all the time) and live preview (which hides the markdown codes except when they’re being edited) a majority of their users choose live preview, while a vocal minority prefers source mode.
In the case of Typora, that’s easy to dismiss as sui generis, because they were the first to offer live preview and made it their primary differentiator, so of course they attracted a user base who preferred it.
But Obsidian offered only source mode for the first several years of its existence, and during that time they experienced the exponential growth of a highly enthusiastic user base. Nevertheless, as soon as live preview became available, most of those users switched to it.
I suspect most of iA Writer’s existing users would prefer it, too, if they could toggle it on. There’s no reason to believe that having that choice in the settings would alienate those users who prefer the current approach, as they could continue to use it as is. The choice would also make iA Writer appealing to new users in both groups.
But as you’ve expressed repeatedly here and on other platforms, you believe that those who prefer live preview are mistaken and are better off without it, and that even visually deemphasizing the codes would make iA Writer worse, even if it’s optional.
You have, of course, every right to make that call. You’re the developer, and it’s your app and livelihood.
While that decision may seem opinionated or paternalistic to some of us as customers and users, perhaps to you as iA Writer’s creator it feels more akin to an artistic one.
But that doesn’t make it pragmatic, at least not primarily.
If you disagree, perhaps you can share why devoting resources to develop a toggle to switch all highlights from yellow to pink was a strictly pragmatic decision, but offering a toggle to visually de-emphasize or hide markdown codes wouldn’t be.