Consider the firm or lawyer being compensated on a contingency fee basis -- they must cover all the expenses and overhead related to prosecuting the case, including the salaries for attorneys and paralegals working the case -- and if they lose they get nothing. Since their reward for winning the case is fixed, at usually 1/3, reducing the time and cost they expend on a case, particularly during e-discovery (which can consume quite a bit of time and manpower), is both valuable and in their best interests.