I think people are forgetting how the international schedule always changes in Lions years. In 2017 England went to Argentina, Wales played Samoa & Tonga, albeit in NZ, Ireland toured Japan, Scotland and Italy toured Singapore (where they played each other), Australia and Fiji and finally France toured South Africa.
England were always due to play USA & Canada this summer. The only impact of Covid has meant that these matches took place at Twickenham instead of in North America. Wales were always due to tour Agrentina, but it worked out easier for everyone, including the Argentine Squad, for them to happen in Cardiff. Argentina are actually the nominated home side. Scotland were always due to tour Romania & Georgia. Obviously those didn't happen but plans only changed when Covid forced match cancellations. France were always due to tour Australia, although the length of the series has been condensed due to quarantine requirements.
The only tours that have changed were that Italy pulled out of travelling to NZ and Ireland withdrew from touring Fiji. In the grand scheme of things it made sense for NZ to play Fiji (they'd have thrashed Italy anyway) and Ireland provided additional opposition for USA & Japan who were in Europe for other matches. Canada used their Welsh links to secure a second match ahead of the England game.
Are they worthwhile contests? To the American and Canadian players who have fulfilled a dream of playing at one of the big national Rugby statiums in Europe, yes. For England? Well it's given many fringe players a chance to show what they can do and experience an international camp. Don't underestimate the value of that.