I just started using Line Webtoon and so far the experience has been positive. I upload my comic to three places. Tapastic, Webtoon, and my own site. I've found the audience at Line and Tapastic seem to be different, or at least a lot of the people commenting on my comic on Line Webtoon have never seem my work before.
There's no reason not to have your comic available to multiple audiences, the only catch being that if you ever get selected for a paying thing... like Hiveworks or Line Featured, they like you to be exclusive. Which just means you'd need to take your series down wherever else it's hosted.