target in tsconfig.json setting not working but command works?

Question

{
  "compilerOptions": {
    "target": "es5"
  }
}

I have tsconfig.json as above, and when I run command tsc app.ts --watch, I hit error

Accessors are only available when targeting ECMAScript 5 and higher

If I explicitly set the target in my command, it works

tsc -t es5 app.ts --watch

Any lead to which part may have gone wrong, why the discrepancy between two outcomes?

UPDATES

Answer 1

Documentation says

When input files are specified on the command line, tsconfig.json files are ignored.

That's why when you run tsc app.ts --watch, your tsconfig.json file isn't being applied. You're providing app.ts.