If matchmaking is based on time played then it encourages less playtime. By playing fewer games, players get matched with others who aren't as good. Playing fewer games also means avoiding premades that queue repeatedly every day.
I have not been playing much lately and I noticed a big difference in matchmaking.
Games from the past week:
Normally I do not have this kill/death ratio.
Usually I go 1:1 or worse.
Based on my experience, I do not think time played should be a factor in matchmaking. It is not fair to others and the matchmaking should encourage more playtime, not less.
If I take a few days off Rocket League, I'll still be the same rank I was at previously and get matched appropriately. ESO battlegrounds should work the same way.
PC NA