Once the sync is done its not a problem. As its only a short space of time to update the sync per block. Running at 3.3v is fine for 99% of the time.
It is a problem if you want to use your device as intended. Website states:
"FutureBit Apollo BTC is the world's first vertically integrated platform bringing the full power of Bitcoin and it’s mining infrastructure in a small, quiet, easy to use desktop device designed for everyday people. "
"At the heart of the new Apollo BTC product is a revamped SBC (Single Board Computer), that is as powerful as any consumer grade desktop system and can run almost any Bitcoin Application natively on the device 24/7. Take it out of the Box, plug it in, power it on, and you are already running a full Bitcoin node without needing to do anything."
Well that's not true. Any application which pins CPU for a bit will cause massive overheat, slowdown or damage.
Fair point. But most people wont be using it as a "Desktop PC".
As crypto_curious said, ideally it would have a bit more space between the SBC and hashboard, at least that way you could install a slightly thicker fan for better cooling. I found it difficult to source a replacement fan in the thickness thats required (6mm) most were 10mm, which IMO wouldve been the better choice for cooling and noise levels.