Enriches WordPress experience

The plugin gives access to backup functionality and monitoring out of the box.
Spelling and grammar correction help a lot with writing articles.
The configuration of this plugin is easy for the most parts.

But there are some aspects I must attend:
The plugin seems like a “eierlegende Wollmilchsau” (a figure of speech we say in German for something, which tries to be everything -> jack of all trades).

The biggest issue for German / EU users is Privacy! In Germany you can get a cease-and-desist warning for using plugins which do not adhere to the privacy laws (it has become a business model for some lawers.)

Speed is also a problem, if you use all features of the plugin.

All in all, Jetpack can help you with a lot of problems out of the box, but you still have to be careful which features you use.