Fox2232:

Not necessarily, it can start with some kind of loader. (Like having cartridge in and active.) It is emulator, and it will not be authentic. As other emulators, it can produce same logical results to same assembly code, but hardware quirks "can't" be emulated.

You can emulate hardware quirks using cycle-exact emulation, but it's quite demanding. Higan for example (previously known as BSNES), does this, and is able to reproduce graphics effects in games that depend on corner-case quirks, but requires something like a 3GHz quad core CPU or something like that to run at full speed. None of these "mini" emulator boxes come even remotely close to be able to provide such low levels of emulation. They only provide a cheap ARM CPU. Another solution would be an actual hardware logic implementation on an FPGA, but again, these "minis" obviously wouldn't ever do that. They need to be dirt-cheap to produce and turn in a big profit. These "minis" do not seem even remotely authentic to me. If you don't put on a cartridge, or put a cassette or floppy in, there's no authenticity to be had for me. Switching this on and being presented with a ROM selector menu just kills it for me. Nothing can replace the feeling of putting that floppy in the drive and hearing it work as it loads the game. It's a big part of the authentic experience. For example, an emulator "mini whatever" cannot replace this experience: [youtube=F1GNx-qlEj8]

Fox2232:

By HW Quirks, I meant no logic expressions. But electrical synthesizations. At the end of each line to human was analog information. (Sound/Video/...) Few unique physical transistors can do and react to signal in ways digital emulation can't do 100% in real time. Hardly matters how many iterations CPU can do, or how wide-bit-depth is. It is digital. Digital can get pretty close. never 100% analog.

I have no idea what this means. The C64 was a digital computer. So was the NES and anything else made in the 80's. Analog computers were made in the 70's and some pong-clone consoles were analog, but that's about it.

Fox2232:

Have you heard about modem? That little box which took digital information and "modulated" it into analog sound transferable via standard telephone line? Guess how those bits from PC of the old got into connected TV. Does PAL rings the bell? How does zeros and ones from SID get to be played? Modulation via electricity handling transistors. Not that much different from modem. Except those transistors on c64, those capacitors, ... All made very unique blend. In all those years, there was no emulator which would sound like physical c64.

You need modeling for that. It can be done. It's been done for the MT-32 emulator, for example (munt.) It models the analog stages of the module extremely accurately. You won't be able to notice a difference. Although you can turn that off if you want, to get higher quality sound 😉 But I agree with you that the original hardware is always the best, because... it's the real hardware. But emulation and analog modeling can give you extremely good accuracy, to the point of transparency. But not many emulators do that. It's hard to do.