[ChrisSD]

I'd also emphasise that fortunately most modern cryptography (outside of one time pads) does not rely on truly random numbers. So long as the sequence is unpredictable enough it's fine (i.e. you can't use known values to more reliably guess unknown values).

The PRNG in the linked page isn't very good but in general PRNGs are super useful in the real world even if they aren't truly random, just so long as they have some source of entropy to occasionally mix into the PRNG.