I got a Core last fall and love it. I had run a dedicated trainer wheel for several years so I was always swapping out the rear wheel anyway so it was no added work for me. The direct drive is better than a wheel on trainer but if you get a killer deal on a used Snap you’ll be no worse off than you are now but a few hundred dollars richer. I would think you might find the 100% no slippage a nice feature for your low rpm high power repeats though. A direct drive trainer really shines in that scenario.
As for removing the rear wheel, there is a technique to it. After getting a car that required me to remove the rear wheel to get the bike in the trunk, I finally buckled down and watched some YouTube videos and can now swap out a rear wheel as quick as the front. If you apply yourself, you can get Tour mechanic fast in about 15 minutes of study and practice.
As for the cassette, the motivation of avoiding having to replace two instead of one if you let your chain go too long might actually save you a lot of money in the long run 