Because as already stated the Android version is essentially Bigbox and not Launchbox. It's also worth noting that the Android version costs money as well, just like Bigbox, so its the same case on Windows or Android, both need payment to get what you want.
No, it is not just as difficult. Those programs use Retroarch for most systems, and you cant choose other emulators a lot of the time. They are very locked down, and you use what they tell you to use. Launchbox is completely user configurable, meaning you have access to tons of emulators that distros like emuelec and batocera don't allow you to use. also those distros are Linux based, meaning you miss out on some of the great emulators that are available on Windows, that are not available on Linux, again because these distros are so locked down and lack customization. I should also mention that i am not just fanboying for Launchbox, i also have a Batocera setup, and i like it, but it does not compare in the slightest to Launchbox/Bigbox, it is way too restrictive and locked down, it's their way or the highway for those distros, which it is not for Launchbox, where you can use any emulator, any image types, any folder name and location, all things you cannot change on the other distros.