Is there some huge benefit that I’m missing?

For example I recently fixed a bug where a function would return an integer 99.9999% of the time, but the other 0.0001% returned a float. The actual value came from a HTTP request, so it started out as a string and the code was relying on dynamic typing to convert that string to a type that could be operated on with math.

In testing, the code only ever encountered integer values. About two years later, I discovered customer credit cards were charged the wrong amount of money if it was a float value. There was no exception, there was nothing visible in the user interface, it just charged the card the wrong amount.

Thankfully I'm experienced enough to have seen errors like this before - and I had code in place comparing the actual amount charged to the amount on the customer invoice... and that code did throw an exception. But still, it took two years for the first exception to be thrown, and then about a week for me to prioritise the issue, track down the line of code that was broken, and deploy a fix.

In a strongly typed language, my IDE would have flagged the line of code in red as I was typing it, I would've been like "oh... right" and fixed it in two seconds.

Yes — there are times when typing is a bit of a headache and requires extra busywork casting values and such. But that is more than made up for by time saved fixing mistakes as you write code instead of fixing mistakes after they happen in production.

Having said that, I don't use TypeScript, because I think it's only recently become a mature enough to be a good choice... and WASM is so close to being in the same state which will allow me to use even better typed languages. Ones that were designed to be strongly typed from the ground up instead of added to an existing dynamically typed language.

I don't see much point in switching things now, I'll wait for WASM and use Rust or Swift.