Class actions allow many consumers with small individual harms to collectively pursue a company; waiving this right means each consumer must pursue claims alone, which is often economically impractical for small losses.
Stash users are subject to mandatory arbitration and waive their right to participate in class action lawsuits, significantly limiting legal recourse if something goes wrong. Stash may unilaterally modify, suspend, or terminate services or fee structures without prior notice, and users' only remedy is to cancel their account. You can opt out of the mandatory arbitration clause by sending written notice to Stash within 30 days of first accepting the Terms.