Yes, all signatures you create with DigiSigner are legally binding.
The U.S. Electronic Signature in Global and National Commerce Act (ESIGN, 2000) and the Uniform Electronic Transactions Act (UETA, 1999) both establish this electronic signature's legality. DigiSigner is compliant with the European eIDAS as well. All of these are recognised in court, establishing that a document or a signature cannot be denied legal effect solely because it’s in digital form.