I'm confused why you think this is confusing? Stellarium is something you use to point a telescope with (and more focused on amateurs), whereas esasky is designed to browse through objects/images/spectra (with science data for scientists)? I don't know how much the overall data would be (given esasky is using a bunch of astronomy standards would be), but we're at least in 100s of PBs here.
I don’t see evidence of 100s of PB of data here. I do see multiple green stars, which I know is extremely rare in the real world. That’s just not a common color spectrum for stars.
And using a viewpoint of a large sphere from the outside just seems wrong. It should be viewed from the inside.
It's not for you, obviously. It's for academics and nerds that are interested in these kinds of data sets and used to have much more trouble finding and consuming them.
To put it nicely: you're not the target audience. This is the astronomy equivalent of the $50000/yr bespoke mechanical engineering simulator. This is not an outreach tool (or a citizen science tool). You don't take this to a dark field with a telescope at night (it's not a skymap), this will be used on a big screen to plan observations, or at an observatory (where you'll have at least 3 screens running). These kind of applications are developed with deep and continuous input from their users, and there's nothing superfluous there.
Who is it that can manage the niche software needed to digest the data sets but have such trouble figuring out how to navigate that web page? Of what use would they be to the academics and weird nerds?
It took me less than two minutes to figure out navigation and how the menu works. If you really want to make an impression in this area it would probably be better to spend time on improving VO-software and organising study groups where you live.
