As a Pro who can do both ,and also play guitar as well i found when i mixed in midi files and some styles my business has gone thru the Roof , I am a good Voc and when i use midi files i ether play the keyboard with a full sound and a layer or play my Guitiar it give me a much fuller sound and with todays keyboards and jump points you can keep your audience going all night .

we should not look down at peaple who use midi files , playing a guitar or piano ect to a midi file take just as much skill as playing just styles singing 40 plus songs a night and keeping your audience involved is where the skill comes in, my audience has grown 10 fold and selling CD's like crazy i think being able to do both with all the skill you have is a great way to offer a different look to your audience.