This is intellisense in JavaScript file:

It shows description and example.
And this is intellisense in <script> block on Vue SFC:

It doesn't show description and example.
This is also occurrs on <script lang="ts"> block on Vue SFC:

<script> block on Vue SFCMinimal Reproduction: https://github.com/jefrydco/vue-intellisense-behaviour
This is a special pre-processing recently added in VS Code: https://github.com/microsoft/vscode/blob/8ba70d8bdc3a10e3143cc4a131f333263bc48eef/extensions/typescript-language-features/src/utils/previewer.ts
I copied it over:

While at it I fixed hover/completion as well:
