It’s pretty. By default, even. Floorp is customizable, but many (most) people want a tool that works directly out of the box, and if it looks good while doing it, then it will be more popular.
The dev advertised it on Reddit, then when people complained about issues, you would see a response from them along the lines of “fixed,” which showed responsiveness, and I think that gained loyalty before the product was ready to be released.
This is a pretty difficult question to answer since all phenomena are quantum. A star is powered by nuclear (quantum) fusion. Permanent magnets depend on the quantized angular momentum of electrons. Could these phenomena be allowed by something other than quantum mechanics? Maybe. But a constant goal of science is to find the simplest explanation for all we observe, meaning that whatever alternative explanations you come up with, should they be correct, then taking them all together will constitute a theory that at least looks an awful lot like matter waves (mathematically, at least).
This is a forum. If you don’t get the joke, you can ask and have it explained to you. Most memes are some form of in-joke regardless, so you often have to do a bit of learning the first time.
What was off about your first comment was recognizing it for what it was before proceeding to miss the joke entirely.
What was off about your replies was trying to compare it to the Scottish coat of arms; if you know the Scottish coa, you probably wouldn’t associate it with piss yellow and white. If you don’t know it, you wouldn’t mix them up anyway.