The main innovation of tree-sitter, even more than incremental parsing, as I see it is that it provides a uniform api for traversing a parse tree, which makes it relatively straightforward to onboard a new language to a tool with tree-sitter support. The problem though is that the tree-sitter grammar is nearly always going to be an approximation to the actual language grammar, unless the language compiler/interpreter uses tree-sitter for parsing. To me, this is problematic for tooling because it is always possible for a tree-sitter based tool to be flat out wrong relative to the actual language. For syntax highlighting, this is generally not a huge deal (and tree-sitter does generally work well, though there are exceptions), but I'd be more cautious with security tools based on tree-sitter.

If all languages changed their reference parsers to tree-sitter, this would be moot, but that seems unlikely. Language parsers are often optimized beyond what is possible in a general purpose parser generator like tree-sitter and/or have ambiguities that cannot be resolved with the tree-sitter dsl.

What feels perhaps likely in the future is that a standard parse tree api emerges, analogous to lsp, and then language parsers could emit trees traversable by this api. Maybe it's just the tree-sitter c api with an alternate front end? Hard to say, but I suspect either something better than (but likely at least partially inspired by) tree-sitter will emerge or we will get stuck in a local minimum with tooling based on slightly incorrect language parsers.