Three thoughts from a newbie

I am a complete newcomer to Steemit and to cryptocurrencies/blockchain products generally. The technology is certainly intriguing, but I don't think I fully understand it's purpose. In some ways, I sort of think that many of these projects are obscure and confusing for a lay user. So I thought to share with this community my initial three, major thoughts on Steemit based on on my (very) limited experience with it and from a lay perspective. Hopefully it gives more senior community members here some ideas on how to make the transition easier to understand for the less experienced.

1. Why and how and what is this payment system about? I read some of the FAQ and 'about' pages but it just seems really weird to me. Some made up currency that essentially represents social interaction? But what's its intrinsic value? The FAQ mentions some possible future Steemit services that these tokens/points could be used on, but as a newcomer to this whole scene I have no idea what that those services are or if they would be valuable to me or my friends. If they aren't, then perhaps I will value the Steemit tokens a lot less, for example.
2. This is the blockchain, an immutable and public record; so how is this site dealing with my private information (phone number and e-mail)? I don't mind attaching my actual name to my online accounts, but I have only just begun to realise the ramifications of providing my private e-mail and phone number to a distributed, blockchain application. Where are my private details held and how are they secured? And I also read in the FAQ that I can't deactivate my account. I think from a lay perspective this is a bit shocking, since privacy and autonomy of personal information/content is a big thing for most mainstream web application users out there (notwithstanding, of course, the very obvious snooping of Facebook/Google, but I do feel that I at least have some privacy there or can at least delete my content or restrict who on the network can access it or be friends with me - Facebook and Google have also implemented policies for what to do when someone dies, and people even write in their wills now how they want their digital accounts managed or destroyed after they die).
3. Is the idea of this system to be something between Reddit, Twitter, and blogs? Why was Steemit built this way, is it due to the limitations/features of the blockchain? I'm not saying it's not interesting, but it does add another hurdle towards feeling like I understand what Steemit is and what its purpose is. Why couldn't this just be done on a centralised service, e.g. offered by a private company? I mean, I can basically post blogs already and share them on Twitter/Facebook/LinkedIn, and for free, and even get paid for it if I want. I don't happen to do this, but people do it. Is Steemit trying to capture that market and then also reward people who like sharing content? It's a confusing proposition and perhaps I am not understanding or missing something major here (so a bit related to point 1).

Those are my three biggest questions/experiences/comments on my initial foray into this little (or, I suppose, not so little and becoming bigger?) community. I'd be very interested to hear from other members of the community about how they use Steemit and what they see as its unique purpose and value.

P.S. And just to clarify, this really isn't meant to be an attack or critique or anything on Steemit or the blockchain community at large. I am just wishing to share my experience and find out more, because like I said I think blockchain tech and Steemit is a very intriguing technology that I would like to learn more about.