If all that you're missing is the script type, there's few enough of them to just guess.

If you're missing the derivation path, you can either remember what wallet you generated from or brute force the defaults list: https://walletsrecovery.org/

But multi-sig is where it gets tricky because the xpubs can't spend your funds, but they can dox your stack. So you can make it more available (upload it to a cloud storage provider) with the risk being that the company you upload it to, or a hacker who may or may not leak the info, will dox all your Bitcoin in all your addresses (knowledge that the addresses all belong to one person), but they still can't spend from it.

You can trade off an xpub's confidentiality for more availability (the security triad)

Its just neat to be able to have it all stamped into a plate. Then, even if you didn't know you needed all that other stuff, you still have it.

Go try it. Find your wallet in this list: https://walletsrecovery.org/

Then, pick another wallet that doesn't have the same derivation path. I'm not saying do it with your main stack, or even a wallet that has Bitcoin in it. Just try it with a wallet that had Bitcoin in it and you'll find that you can't get your wallet history or even the same Bitcoin addresses to show up.

Not really an argument to be had. Its a technical reality.

I have to comment on the seemingly strange company shilling in your question, but to answer:

If you have ALL seed phrases, you don't need all xpubs. You can generate the xpubs from the seed phrase and derivation path. However, if you have only 2 of the 3 in a 2 of 3 (say the third one was lost or stolen aka an availability issue) then you need all three xpubs.

xpubs and derivation paths are all about helping you find which utxos belong to you that you can sign. There are other ways you could accomplish that end, but they are more complicated (like storing every Bitcoin address you have ever sent coins to, or storing PSBTs) than just backing up derivation path, script type and xpubs.

The software and experience is quite user friendly but you'll need to make sure you understand what you're doing lest you make a mistake.

First, you'll need to generate a few private keys offline. You can use the SeedSigner (same hardware) to do this if you want or hardware wallets. Then you must create a wallet descriptor using these private keys. It is imperative that while doing this you don't expose your private keys on an internet connected computer.

Then, on the SeedHammer controller, you need to enter each private key and scan the wallet descriptor. Be sure to check that the descriptor contains the same private keys you generated in case the computer you used to generate the descriptor is compromised. Then all you need to do is follow the instructions on the screen of the controller which is periodically changing plates. Each plate engraving takes a maximum of 20 minutes. The engraving is very loud though so you should do this in a place where you won't disturb people. I had to stop because my apartment neighbors complained.

The device itself has no memory or storage (it's intentionally chosen because it's dumb) so you can loan it to whomever you want. If you're more paranoid you can use a new controller (Raspberry Pi) if you're borrowing someone's but as long as you personally prepare the SD card (and verify the software) then you'll be fine.