When I got into Ubuntu MATE I had just came out of a long hiatus from Linux. That Welcome Screen was a savior, especially because I messed up somehow and was having trouble with my package database, which the welcome screen helped me fix. Today you or I may not even look at it and just disable its “start every time” feature. But I’ll be damned if I don’t immediately recognize its importance.
It shouldn’t matter, who does it or how many do it. What I can tell you is that no one ever did a correct Welcome Screen until Ubuntu MATE. Welcome screens used to be common on Linux. Maybe you just don’t remember anymore, but they were a common feature back on the 90s and early 00s. Almost every distro had one. It was exactly because they were badly made that they fell into disuse. It’s a bit like the FAQ you see on every website. There’s never been in computer history such a misused term as Frequently Asked Question. There was a time they were good, way back in the BBS days and the early WWW days. Bout oh boy did they evolved into pure nonsense. Nobody cares for FAQs these days, due to how lame they usually are. But that doesn’t mean that someone can’t make them right. And Ubuntu MATE did the Welcome Screen right.
And how do you expect to walk a newcomer to Linux through Synaptic or, worse, apt-get? Tools like this exist and become useful after a certain number of hours have been spent using a distro. In the interim, a new user will welcome options such the Welcome Screen and the Boutique. And this is fact! Can be proven with the constant flux of positive user feedback that both applications consistently have on this forum. You seem like a new user to Ubuntu MATE and an experienced Linux user. So it’s conceivable you may look at both apps as useless to your needs. Just don’t confuse your needs with the needs of everyone else. You will lose. Badly. Because you have no idea how much positive feedback both tools have been having from our users. Heck, Boutique in particular even from the seasoned user crowd like myself who still use it to this day! I’ll use Boutique every time, because I trust it to be maintained for me and spare me the work of having to maintain my own repos/ppas for those applications on the boutique. In fact the Boutique is yet another case of someone finally doing a Software Center the right way!
And you also have to consider that a wiki as you say.
It takes a whole lot of effort to write and maintain. Something that is not at the reach of a distribution like Ubuntu MATE that doesn’t share the same number of active users like Ubuntu or Arch. A wiki on the case of Ubuntu MATE would be more detrimental give the high probability of it contained poorly written content (as is the case of the poorly written Manjaro wiki). Neither can you expect new users to know what they are looking for. What good do you think a wiki will do to a user who can’t update Ubuntu MATE because his package database needs to be fixed? Don’t confuse Ubuntu MATE with Arch. This is a distro that also wants to include a different audience: those who lack experience on Linux.