But yes, it is safer to use EAD after one's I140 is approved.
So you have to balance things here. If your spouse needs the job badly, then go ahead to use the EAD. If not, then he/she'd better not use it and stay home.
It is not so bad to get an H4 outside the States. I've mentioned before several times that my friend's wife used her EAD before his I140 approval, and his I140 got messed up once, and their I485 expired, so did her EAD. She immediately left for China and got her H4 and safely returned.
So, in this case, you remain your H1 valid is the important issue. I think she is okay to use EAD to work.