Yes Grab, the miniature microphones can be used on guitar as well, and some people have been doing this for years. Audio-Technica came out with a small bracket maybe 20 years ago that slides onto the guitar top at the soundhole and positions a small condenser mike close to ths strings (kind of like the tie-clip that holds the lavalier mikes used by sportscasters, etc. -- but without the strong spring and "teeth" that would damage the instrument's top). The sound is very dependent on positioning and direction (millimeters make a difference), and feedback is still an issue, but it's definitely an option that can yield a very musical tone. I think the bottom line is that none of these options is perfect, none exactly duplicates the acoustic sound of the instrument, but all are worth exploring. My favorite local music shop (The Music Emporium in Lexington, Massachusetts, USA) has test instruments set up with a variety of their "most favored" pickup options, so you can compare and contrast -- which really allows you to identify what it is you like and don't like about each of the available options.

As for what is "harder" or "easier," there are a lot more factors at play here than how much resistance is under your fingers when using acoustic vs. electric strings. It comes down to touch, what you're trying to play, and how familiar you are with how the various components work together. On an acoustic guitar, you have fewer ancillary pieces of gear, but you still need to adjust your touch to get the sound projection and tonal nuances you're after. Same with electric -- for all the outboard sound-processing stuff people employ, it still comes down to conveying what's in your heart and soul by moving your fingers around on the strings. The best gear in the world won't make up for lousy technique.

I've never known an exclusively acoustic guitar player to be able to pick up an electric guitar and instantly make it sound good, nor have I known an exclusively electric player to be able to do this with an acoustic. They're different instruments, and each offers its own challenges and rewards -- all it takes is time and patience.