Cordless Polishers have their place, and bring some real advantages om situations where there are no outlets to plug into. Bringing a few battery packs beats haulting a generator any day.
However, in the rust to go cordless, remember that there are disadvantages to cordless tools as well. In a professional shop, where polishers are used all day, the problem is charge cycles. How many charge cycles can the battery pack go through until the performance falls off to the point that the battery pack must be replaced? In a shop that runs polishers for 6 hours a day. that is 4 recharge cycles per day, per polisher, for each battery pack. Assuming 300 recharge cycles as a lifespan, that means that the battery packs must be replaced every 75 working days, 15 weeks if the shop is running 5 days a week. That is BOTH battery packs. The numbers are obviously subject to modification: Maybe the shop runs the polishers for longer than 6 hours, or less than 6 hours. Maybe that battery packs can have more charge cycles. Point is, that in a production shop, there are going to be a lot of battery packs required to be replaced. This is also makes an assumption that the battery packs are used optimally. Running the lithium packs until dead flat will reduce the charge cycles. Pushing the machines hard will mean that the batteries will not last the full 45 minutes.
For a home user, the problem is the opposite. Because the polishers would not be used regularly, the battery packs will be sitting unused for periods of time. This is also bad for the battery packs.
This isn't politics. or opinion; it is how lithium battery packs behave, whether they are in cell phones, laptops, or even cars. There is a wear-out mechanism that cannot be escaped. Some battery packs can have 300 charge cycles (most), a few can have 1000. I don't know which the Flex battery packs Flex uses, or their charge cycle ratings. They will wear out, eventually.