He’s right. The erasure codes require reconstruction of the data and there is built in error correction (is it parity blocks for storj?) and these are used for reconstruction of the data. So if a bad or lost piece is asked for then that has to be reconstructed from the other blocks requested. And I gather normal blocks of data are still reconstructed from 2 “half” blocks using the reconstruction process.
This process is similar/same as the par2 blocks used for nntp and it has long been a problem when used against many GB files. Now Storj is not doing that size erasure codes, but the point still applies that in order to reconstruct a certain amount of capabilities are needed and if desired to be done in a reasonable time then it needs more speed and memory.
So the downside is that there is a limit to how small the device can be. Whereas for the SAFE network the device basically has to be able to web browse and it will be able to surf the SAFE pages/network since the crypto/capabilities needed is pretty much the same as what is required for hhtps