Oh dear, here I go again preaching from my soapbox
Cheap products promoted as universal fix-its [otherwise sometimes described as "answers to a maiden's prayer"
] in my experience, backed up by discussions with others who have expertise in this field, invariably prove to be partially effective at best or a complete waste of time and money in most cases.
I would never take a pool shop recommendation as guidance for use on motor vehicles and vice-versa; the elastomers used in pool equipment are completely different formulations to these used in automotive applications. My reason for this is my 5 years experience working for Australia's leading pool pump, spa pump and filter manufacturer.
A lot of research has been undertaken into seal conditioners/lubricants for the Eos and other vehicles to determine the most appropriate product
and the Eos has now been on the market long enough for the effectiveness of the recommended products to have been tested by owners right around the world.
Suffice to say, the recommended VW product and the Krytox GPL105 equivalent have proved their effectiveness over time and their cost of their use is minuscule compared to the other costs incurred in owning and running a car. At the risk of sounding repetitious; "first cost is not always the end cost" and "the quality of the product is remembered long after the price is forgotten".
Why risk permanent damage to an important car component for the sake of "penny-pinching" given the cost and/or loss of vehicle value associated with roof seal problems?