A border router that is not able to serve blocks is still protecting consensus rules, that SPVs do not.
If the network would only consist of SPV nodes only then e.g. a majority coalition of miner could increase their reward at will.

Archives need a different solution.

Regards,

Tamas Blummer
http://bitsofproof.com

On 09.04.2014, at 17:47, Mark Friedenbach <mark@monetize.io> wrote:

On 04/09/2014 09:09 AM, Tamas Blummer wrote:
Yes, SPV is a sufficient API to a trusted node to build sophisticated
features not offered by the core.
SPV clients of the border router will build their own archive and
indices based on their interest of the chain therefore the
border router core does not need to store (and process) anything not
needed for consensus, its memory
or disk footprint would be as low as an optimal storage of UTXO.

Storing zero full blocks does nothing to aid the network.