It's not really abuse but also a bit unnecessary especially since communities do a good job at separating your posts. I think it's most likely better to focus on one account than splitting it up due to the activity of them and your followers maybe not realizing that it's yours or having to follow that one too, etc.

Only reason I could think of getting an alt is if you don't want to risk getting autovoters to lift you off of their voting lists if you post something they wouldn't want rewarded or less effort content, but even for that there's ways people can forfeit part of their post rewards now to send to @hive.fund or other non-profit projects for posts they deem shouldn't get as much rewards as your usual creations.