It's not at all obvious based on the title. Many people don't know about sideloading.
The important part of this discussion is not on the user side. Yeah they can sideload but really they won't do that because of IAP, of all things.
The important part of this discussion is on the developer side. Going through Google will mean they get to shape what apps developers can even economically build without falling back to sideloading (which just won't happen, see above) and we already see how "great" that in the iOS ecosystem.
Of course, you are in camp "IAP means clear and central subscription management, it's great for me!" then you might not care or even welcome this.
I happen to be in camp "What is good for the user should not be contingent on the business model allowing for a 30% cut going to google." There are and will be products/services users want, but not at 1.30 times the price, and those will simply become impossible now.
On the other hand... Let's just watch Rome burn and then see what we do with the ashes?