There are both, every user has their own sandbox. But this one is there to encourage first time visitors and the uninitiated to make changes , so they know that anyone can contribute uninhibited.

It's interesting to think about how complex the wikipedia text is compared to something like github flavored markdown or even standard html tables (although I guess it eventually renders into standard html so it's not more complex than the latter when all other html elements are considered in addition to <table>)

For example the swatch internet time infobox is dynamically updated

{{short description|Alternate time system by watch maker Swatch}} {{Infobox | image = [[File:Swatch beat Logo.svg|200px|alt=Logo of Swatch Internet Time]] | caption = Logo of Swatch Internet Time | title = Time{{efn|at page generation }} {{purge|(update to view correct time)}} | label1 = 24-hour time (UTC) | data1 = {{nowrap|{{#time:H:i:s}}}} | label2 = 24-hour time (CET) | data2 = {{Time|CET|dst=no|df-cust=H:i:s|hide-refresh=yes}} | label3 = .beat time (BMT) | data3 = {{nowrap|@{{#expr: floor( {{#expr:{{#expr:{{#expr:{{#time:H|now + 1 hour}}3600}}+{{#expr:{{#time:i}}60}}+{{#time:s}}}}/86.4}} )}}}} }}

I just went back to check whether I have a sandbox on Wikipedia. Turns out I do: https://en.wikipedia.org/wiki/User:Susam_Pal/sandbox

I am not a regular contributor to Wikipedia but the little time I have spent contributing there has exposed me to its very elaborate culture, with barnstars being one artefact of that culture, alongside policy acronyms everyone seems to know by heart, WikiProjects organised around every imaginable topic, userboxes that are little badges that say something about you, etc.

By the way, I added a few userboxes for the Logo programming language, in case there are any Wikipedians out here who happen to love Logo: https://en.wikipedia.org/wiki/Category:User_logo

Pretty much all wikis would have a "Sandbox" page for trying out that particular wiki's individual syntax and features.

Tried to edit on my mobile (T-Mobile - US) and got this:

  Your IP address has been blocked     from editing Wikipedia.

  Blocked by Xaosflux

  Block will expire in 7 months

Curiosity led me to Xaosflux's Wikipedia page where I see they have been active since 2005 with over 85k edits!

https://en.wikipedia.org/wiki/User:Xaosflux