Dashcams normally use lower bitrates than action cameras so that they can fit many hours onto a memory card, for the cheaper cameras that is probably the main issue since they still tend to have a maximum memory card size of 32GB, although many also have low quality sensors, lenses, and don't forget the microphone.
Image quality on the Viofo MT1 is pretty good, same quality as an A129 car dashcam, still lower bitrate and resolution than a GoPro, but adequate and in low light or at high speed it has much better image quality than the GoPro, also because it is a dashcam, it will try to record detail in the shadows when a GoPro would not bother, instead preferring a high contrast colourful more impressive image even though there is little detail in parts.