Interchange Optimization is only applicable to a certain group of merchants. While you might see some B2C (business-to-consumers) merchants getting more interchange downgrades, the real opportunity and most value can be seen in B2B and B2G merchants accepting Visa and MasterCard cards.
Interchange optimization offers the most savings when corporate and purchasing cards are used. Additionally, these B2B and B2G merchants have higher average transaction sizes too making this approach even more valuable.