This is why it is gross.
The selectivity of when to really try to win. When to really play hard or play at your peak. This is how you get Super Bowl champs who go 9-7. This is why the NBA has to threaten teams who sit their best players whenever. It's specifically designed to extract meaning from regular season games. What sense does that make??
meaningful season > meaningful playoff
(even if by sheer volume alone)
This is how I view it. Every playoff expansion necessarily dilutes the importance of regular season games.
In basketball we have a system in which the playoff is very large so individual regular season games are nearly meaningless. They matter in the aggregate, of course, but if you look at one game in isolation it is nearly meaningless.
In football pre-BCS we had no playoff so individual regular season games were hugely important. One bad day at the wrong time prevented numerous great teams from winning the big prize.
Then we went to the two-team playoff that was the BCS. Individual games still mattered a lot, but somewhat less because there was a much better chance of getting a second chance.
Now we have a four-team playoff so some games, for some teams are basically meaningless. Still, individual games are very important, note that Ohio State has missed the CFP because of a single loss in both 2015 (MSU) and 2018 (PU).
When we expand to an eight-team playoff it will further dilute the importance of individual regular season games. That is unavoidable.
All of that said, I do not think that there is necessarily anything wrong with favoring very different systems for very different sports. No matter how much you love the 64/68 team CBB playoff, it simply isn't possible in CFB where you can only play once a week and the game is hell on players physically. It would be crazy to ask CFB players to play up to six or seven more games in a massively expanded playoff.
Personally, I like having a meaningful regular season in CFB and a huge tournament in CBB.