After the submission of ITR, a taxpayer can verify the ITR within 120 days. Now the processing of ITR by CPC starts only after the e-verification of your ITR. Hence, the earlier you verify your return the sooner ITR refund process will start. Now, after processing the ITR by CPC at the primary level for arithmetical errors etc, the refund issue will be on the basis of tax payable and earlier tax payments. So, if there is a delay in verification, the processing and refund will also be late.  Also, nowadays e-verification is more popular and preferrable than physical verification. Firstly, the process is online and easy to complete. Secondly, it saves time. The physical verification can take up to 5 days but online verification finishes within minutes.