Value of Aurora R7 Chassis /w higher wattage?

Hello

I'm thinking of buying an Aurora R7, but I'm wondering what the value/influence of buying a different chassis would be.

Intel® Core™ i7K 8700K (6 cores/12 threads, 12 MB cache, overclocked to 4.6 GHz on all cores)

Windows 10 Home 64bit

NVIDIA® GeForce® GTX 1080 with 8 GB GDDR5X

16 GB, DDR4, 2.666 MHz

256 GB PCIe SSD (bootdisk) + 2TB 7.200 rpm SATA 6 Gb/s (storage)

8 x DVD+/-RW 9,5 mm ODD

Qualcomm DW1820 2x2 802.11ac Wi-Fi Wireless LAN en Bluetooth 4.1

460 W EPA, chassis with aircooling with ODD

So, I have the choice between a 460W chassis, and a 850W chassis. The 850W model is 140 euro more expensive.
Since I'm also able to configue it with a 460W Power Supply(PSU), what would the value be of spending that much more money on a better PSU?

I know generally a higher wattage is 'better' / 'safer'  in terms of the possibility of components being able to pull too much power for the PSU to handle, but since this is a pre-built PC, I would assume that since I'm 'able'  to configure it with a 460W model, that would be sufficient (only thing I can think of is future-proofing in the case I'd want to add another GPU, but adding another HDD or something should be fine with the 460W model aswell right?)

Could someone maybe elaborate on this? 

Cheers,

Chris