I often find it necessary. Most arrangers don't have old-time country styles, with perhaps walking bass.
I take a Big Band or Jive style, change the sounds--brass to guitars, maybe strings to vocal OOOhs, change the bass sound and/or drum kit. It's pretty easy on most modern arrangers. You find a style that is close and make it sound like you want it to sound.
Other styles often sound better with different sounds for the style parts, or perhaps mute some of the style parts.
Many Korg styles have abrupt endings that are not musical at all. You can edit and fix those with a little time, although I usually just play around them. It's my biggest pet peeve with Korg, those style endings sound like someone just pulled the power plug and they stop dead, no sustain, no riffs, nothing.