What's with you and constantly trying to have me say the complete opposite of what I said?
YOU WILL TAKE IT TO OTHER SETTTINGS AND OTEN ARRIVE WHERE PLANAR PORTALS ARE NOT PRESENT.
Which of the major settings or planes of existence doesn't have a portal, but is easily reachable via a Spelljammer?
Or the 99.99% of the various universes where no portal from Sigil exists. Sigil is finite in size. It does not have infinite portals to all places in all settings. It doesn't even have portals to more than a very small percentage of places.
That is quite literally the opposite of how Sigil is described.
In the 5e DMG: "Called the City of Doors, this bustling planar metropolis holds countless portals to other planes and worlds."
From the Wiki, referencing the 3rd edition manual of planes and the 2nd edition Guide to Sigil: "A major hub for interplanar travel,
the city contained multiple portals to every single plane, as well as to numerous locations in the Prime Material Plane.[4][2]" and "Thus, the city touched all planes at once, yet ultimately belonged to none."
Further more, since you could not enter or exit it except from a portal, and could not observe it via any magic, and there is no reason therefore to consider that it could not be infinite in size, or infinitely layered.
First, it's only you, not we. Second, I said planar travel is far more dangerous, so again you're attributing to me the literal opposite of what I said in the post you quoted. Stop it.
How is walking through a portal more dangerous than sailing through explosive gas full or monsters and pirates for months at a time?
It's not like there's an Office of Portal use that shows everyone a convenient portal to wherever they want to go. You have to get lucky to find a portal to exactly where you want to go. Or hell, even a portal anywhere. That portal to Krynn you want? Well it's on the 17th level of Undermountain and you have to have a severed green dragon head to trigger it.
And once you find a permanent portal? You can always go back to it, it is permanent. A severed green dragon head? Okay, hard to initially get, I will give you that. It isn't like Sigil is a trading hub of the entire multiverse where you can buy anything and everything given enough time and money. Or that something like, ritually casting Gentle Repose every couple of days will keep a single severed head from decomposing allowing you easy access to the portal for... forever.
And again, how dangerous is spelljamming again? With how many groups of slavers and pirates who are waiting to kill people, or monsters, or the various other things that you might find. I mean, aren't their reality storms and the like which can time displace you and make your journey take 100 years?
Yes, it is hard to initially set up a portal, but once it is set up? Walk through and arrive. Far simpler, far easier, far safer.