Presenting data in "context" means that you personalize based on the data you were able to collect. This concept brings a limitation on the type of personalization you can achieve, you can use contexthub to personalize based on the things that are known of your user or things that you were able to collect and reference in future. You use this type of personalization when you are sure of the type of personalization your site will have, you don't need to measure, nor figure out what type of experiences you would need. Adobe Target goes beyond that, by leveraging AI to understand and personalize beyond what you know of your customer, e.g. recommendations, etc.
If the user starts a session on desktop, abandons it in between, and logs in on mobile, does it still show personalization? That's a good question, again the answer depends on which data is available on mobile at the moment the page shows up to show the experience.
I also see that ContextHub does not involve any coding. Not necessarily, true, but if you stick to OOTB segments it may be true, but you could still need some extra custom segments https://experienceleague.adobe.com/en/docs/experience-manager-cloud-service/content/sites/authoring/personalization/audiences.
Additionally, I would like to mention that, in my opinion, ContextHub appears somewhat outdated and has been somewhat neglected. There are some known issues regarding performance, and the documentation on how to customize it can be quite messy.