What are the benefits of languages that are not Turing complete?
The main advantage of having a Programming Language that is not Turing Complete is that your language can be strongly normalizing, that is, you can ensure that all terms halt with a unique, well formed value.

I've come across non-Turing complete languages primarily with proof assistants. When you're using programs to prove theorems, you need to make sure that all terms halt, since otherwise you can produce non-terminating terms of type False. This also ensures that type checking is decidable with dependent types, since we need to evaluate code with type checking. Agda and Coq are both languages that are not Turing Complete. This also ensures that you can't accidentally write an infinite loop, which is the motivation behind things like the Dhall language.

As for what you mention about program analysis, Rice's theorem means that any analysis of a Turing Complete language is either unsound or incomplete. So if you use restricted languages, you might be able to write analyses that are precise.