Much of web development doesn't need extreme levels of attention to safety. A good fraction of web development is such that errors are quickly caught in manual testing and at worst just make some button look weird for the short span of time before the problem is noticed and fixed. Also, time spent using generic safety tools is time that could instead be spent reworking and better understanding the specific code to make it safer. There is a lot of cultism in the industry about testing and type safety. I have seen people demand almost 100% test coverage for code that displayed some extremely simple UX which, if it broke, would be completely obviously broken the first time you tried actually interacting with it. I have seen TypeScript used for short code that basically just displays simple UX and is made up largely of calls to third party libraries anyway. I think there is no generic appropriate level of attention to safety. It depends on the context. If you're working on code that controls a spacecraft or a medical device, it makes sense to spend an enormous amount of thought and work on safety. For much of web development, that just doesn't make sense, but organizations seem to often fall into a trap of mandating bondage-and-discipline features for stuff that doesn't need it - why, I don't know. Maybe because there's an impression that "everyone else is doing it". I guess also, some people just enjoy it.
But I don't enjoy it. I like writing JavaScript. I think I can often do it elegantly and that the perceived elegance at least somewhat corresponds to objective quality. TypeScript makes my code uglier, to my taste at least, and makes development less fun for me. This impacts not just my feelings, but also my productivity. TypeScript had better provide me with something great to make up for this. I rarely make the kind of errors that TypeScript is capable of catching or feel like I need the help with readability and code discovery that it provides. But other people, I recognize, do benefit from it sometimes and in any case, other people pay me to use TypeScript.
But I don't enjoy it. I like writing JavaScript. I think I can often do it elegantly and that the perceived elegance at least somewhat corresponds to objective quality. TypeScript makes my code uglier, to my taste at least, and makes development less fun for me. This impacts not just my feelings, but also my productivity. TypeScript had better provide me with something great to make up for this. I rarely make the kind of errors that TypeScript is capable of catching or feel like I need the help with readability and code discovery that it provides. But other people, I recognize, do benefit from it sometimes and in any case, other people pay me to use TypeScript.