Just curious to hear different people's perspectives on this if anyone cares to share.
As I've cleared content this year from beginner through all of 9.1 (and some side content), my sources of units have dried up.
Thanks to the gracious advice of some forum members, I did figure out how to get the infinite streaks, but it still takes me about 2 hours to clear each of the two main arenas. (I wish I could do the 4 star arena easily too, but I only have a handful of ranked up 4s).

So just taking the Border Tribe one as an example, that's 2 hours for 135 guaranteed units and, even assuming good RNG, maybe like 65 units on the chips. So 200 total. Heck, let's go crazy RNG and make it 270 total.
Now if we take the worst unit deal you could possibly buy, the Peter Parker 135 units for $5, or 270 for $10, that comes out to $5 worth of units for an hour of grinding Arena.
It's kind of a bitter pill to swallow because I would not do anything I didn't enjoy for $5 an hour. That would be absurd.
I still kind of enjoy arena for now, especially for testing out new champs or new strategies/tactics, but I can see it becoming tiresome pretty soon.
So, if you do find it more of a grind than enjoyment, how do you justify it?