So they 'allow' small traders to operate under the radar but any larger retailer is going to have accountants/tax consultants who will advise that while the retailer itself may not be breaching tax law, as long as they convert immediately upon transaction to fiat, their customers mostly will not likely be recording, reporting and paying the tax due on their purchases. The retailer thus could risk being identified as enabling/association with tax evasion by its customers. Most large retailers will run a mile from taking such a risk of association with tax code violation. The whole thing is slyly intended to 'discourage' (obstruct) adoption by retailers by making legally compliant retail level MoE use of Bitcoin effectively impractical.