While the initial weapon quest was very short and very simple (and the process to get more weapons is even simpler), I'm not sure why everyone seems to be coming at this from the perspective that this is all we're getting. They've already said that there will be a more involved process (or multiple processes) to upgrade the weapons. That content is still coming and may end up being just as long/hard/grindy/etc. as anything we've seen in the past.

Essentially gifting everyone at least one Relic weapon is a way to get everyone invested and get their foot in the door. If it was a huge grind just to start with a potential long road ahead for it to even be of a comparable strength then you're immediately making the whole process a non-starter for a lot of people. But if you've already got the weapon and are using the weapon and liking it, then are given a way to make the weapon you already use better? It's a simple appeal.