A six string banjo tuned like a guitar is just a really shitty sounding guitar.
The tuning of the instrument matters and contributes more than you think to the character of the sound. Just as much as the notes you play, if you're strumming, doubling the melody, fingerstyling the hell out of it, or whatever.
I've seen a few guys hacking away at 4 string banjos tuned Chicago style in 'plastic paddy' bands, they all sounded like garbage. Tune the damned thing how it's traditionally tuned if you're going to play it. For Irish stuff, that will be G/D/A/E, an octave below the fiddle. It makes a difference.
For jazz, it'll be Chicago tuning or C/G/D/A, same as a viola.
Take the time to learn the style. It matters. A LOT.