Which is why I said “if you live on the border, sure.” But the cities you mentioned combined are a tiny part of the population while over half the state lives in King/Pierce/Snohomish. If they’re buying enough alcohol that it’s skewing statistics for OR/WA sales, then party in Lyle!
Surely, the Seattle-Portland distance would never be relevant. If there are shops just across the border on all of the major roads (as there probably are), then those shops are where the Washingtonians would go.
Whether the trip is worth it might depend on how much you buy at once. Going once a year and filling up the trunk of your car is different from going every week for one bottle at a time.