You do not have to be a solo musician to benefit from using loops in your recordings, especially if you are recording a song built around a repetitive riff, hook or drum pattern. Often you will find that a certain measure of a take is uniquely perfect, or contains some miraculous imperfections that would be impossible to reproduce. Rather than having to try to play that part repeatedly, just turn it into a loop.
Loop-based music tends to take the emphasis away from the development of individual instrumental parts and puts it instead on development through layering, which is an exciting new way to approach song writing.
Too often musicians make sloppy attempts at using loops to simulate live playing, expecting the listener not to hear the difference. When done right, this strategy works, but more often than not it gives the song an inexplicably robotic quality, and makes it lose that "human element" that gives life to a recording.
More importantly, looping threatens to take the place of real musicianship, such as that between band members who have learned to listen to and play off of each other. Theoretically this kind of interplay can be mimicked with loops, but in actual practice it tends to fundamentally change the nature of recorded music, often for the worse.
With loop pedals and laptop computer programs, you are now more empowered than ever as a solo musician to reproduce your music live. DJs and electronic musicians have been playing shows with loops since the early 1990s, but an increasing number of musicians are finding ways of combining loops with live instruments. Trigger drums, bass lines, guitar riffs or even vocal samples while you play your instrument alone or with a band.
First of all, loops cannot play along with you; you have to be the one making the effort to stay in time with the loop, which is harder than it sounds. For example, combining live drums with a drum loop requires a extremely solid drummer who can hear the loop well and stay in time.
Also, as with using loops when recording, looping often takes the place of what could be a more entertaining live show. Instead of playing with a group of back-up vocalists, you simply trigger a loop of their vocals that you recorded beforehand. This might be convenient, but real musicianship is hard to beat, even with technology on your side.