As a practicing litigator, it is not that simple. Most questions these days are actually questions of mixed fact and law, which involve the application of complicated law to complicated facts. In any event, accounting rules and such are questions of fact, not law. The jury has to understand the law and the facts to know how to apply one to the other.
Second, challenges are limited, so counsel have to accept the lesser of evils when it comes to jury selection.
It is for these reasons that most other advanced democracies with legal systems that derive from the English common law have greatly restricted the use of juries especially in complicated financial matters. The United States is a backwards outlier in that regard.
As well, juries do not give reasons for their decisions, so an appeal for errors in the actual decision making process of the jury is very limited. The jury can theoretically make any decision it wants without accountability.