so I'm just gonna ask the question
Did you have a specific question or is it just "Should Badjamin buy an All In Plan" - which is kinda hard for anyone but you to answer.
If you are happy using a main dealer service and want breakdown cover then the warranty element is almost free or at least very cheap.
If you prefer using independents and have similar breakdown cover then the warranty element is potentially more "cost" for your situation.
The service plans don't cover everything. Notable exceptions I've already found are brake fluid changes and DSG servicing. They're essentially only the core service items.
The breakdown cover is mostly AA but it is through a VW dedicated call centre and there are the VW silver vans that are VW techs not AA - many people have found that VW Assist can get you booked in faster for serious faults, and sometimes bypass the diagnostics stage. Direct AA cover will not have that potential benefit.
The warranty element isn't as good as the factory warranty, but it's better than most third party warranties. Some common and significant faults are excluded, oil leaks in particular with the crankshaft seal and any perished pipes, but other faults are covered, the DMF and EGR being ones often mentioned. Double check the van warranty conditions not the car ones if searching via Google, despite both being branded "All-In" there are differences.
If your van doesn't have a complete VW service record or VW parts in its history before your ownership that may cause some friction on any warranty claim.
If you don't have any warranty cover currently (and I assume you don't) then be aware that you will not be covered for any warranty claim in the first 30 days - this is to stop people waiting until they have a fault and then taking cover out - something to keep in mind if you are waiting to see if an offer comes up.
At the end of the day it's an insurance and about certainty and predictability. If worrying about sudden costs is an issue you may value paying the cover cost. Yes it won't cover everything you may need in a service and not every fault may be covered but hopefully enough is to reduce the sudden costs.
If cost is your main concern then you may worry more about are you getting value for money.
Personally I've used main dealer service and service plans for a long time on the XC70(s) and intend to do the same on the Caravelle. I also run a regular saver type account to put money aside for work not covered - the XC70 is now at 250k and has stuff failing and the Caravelle is going to need a DSG service soon. But that fits my circumstances (I worry more about surprise costs than regular costs and I've found dealers I'm happy to use so far) what fits yours is somewhat up to you.