Electric guitars with passive pickups will always sound better through a “hi-Z,” or high-impedance input. This is because you want to plug your guitar into an amplifier, direct box, preamp, or audio interface that has a higher impedance than the guitar pickups, in order to make sure they see a proper electrical “load” at the other end of the cable. If they don’t, it can affect the tone in negative ways.
Generally, the 1M-ohm hi-Z inputs found most commonly on modern guitar amps, DIs, preamps, and so on are more than high enough impedance. However, if you’re using piezo pickups to record an acoustic guitar direct, a hi-Z input with an impedance of 2M-ohms or even more may give you better results. That’s why many high-end recording interfaces have hi-Z inputs with as much as 3M-ohms to 4M-ohms input impedance.