It has positives and negatives.
For one, if you get bored working on one comic, you have options. And if you're the type of person that thrives on that, have at it.
Personally, I need to focus on one thing at a time. Sometimes, if I finish a chapter or a few pages of one story, I will work on the other story, but I pretty much have to completely switch my momentum over to the new story.
I want my Patreon to be full of extra comics outside of my main series. 12 pages a year (one per month) as opposed to 52 pages a year (one per week) on my main series.
But in order to get to that, I gotta give my main series a huge lead so I can focus on new projects, otherwise I wouldn't get anything done.