From the posting perspective it will cost not too much posting on both chains.
The following and voting perspective may be more difficult to handle.

If both chains stay successful, wow, we all would have doubled crypto capital.
All in one we have something to do in this disease shutdown period ..... . Interesting will be, if the games and services with #STEEM in their names will decide on which chain to reside, or to build up on both chains with a #STEEM version plus a #HIVE version.