My observation of this is that it's a lot better than people are making it out to be. Transferring your Pokemon has only been free once and that was when transferring from Gen 3 to Gen 4 with a DS with a Gameboy Advance slot. Every other time after that, you needed another device or PokeBank, so transferring Pokemon being behind a paywall isn't that unusual. The only issue being if you don't intend to pay for the yearly premium subscription and you transfer more than 30 Pokemon that aren't in SwSh, you'll either lose the 31st Pokemon and so on or be forced to keep your premium subscription until you can transfer then to SwSh or when they're usable in later generations. This is essentially holding your Pokemon hostage unless you pay for premium until some of your Pokemon become available in the expansion packs or in later generations.
Other than that, Pokemon Home Premium is pretty sweet. You can GTS trade up to 3 Pokemon at once or Wondertrade up to 10 Pokemon at once (a great way of giving out breedjects). You can also host and do room trades as well as normal trades, but I mainly care about the other two. The best thing is that you can do these from your phone and the phone is faster and usually has a better internet connection than the Switch.
When you pay for Premium, you're paying for 3DS transfer and storage capabilities as well as better trading capabilities but that is otherwise it really. Premium is only aimed at hardcore players who still play the older games and intend to eventually and slowly transfer Pokemon as they need them, while also giving them the storage necessary to hold all of those Pokemon. Otherwise free Pokemon Home will be more than good enough for most people with it allowing you to use GTS as standard and do up to 3 wondertrades at once as well as normal trading, all from your phone. It also allows you to move up to 30 Pokemon at a time between Pokemon Switch games.
Personally for me, I'll subscribe to the premium service after Frozen Tundra comes out since that is probably when I'll transfer Pokemon to Pokemon Home, once SwSh is at it's largest capacity, but I'm thinking of doing only the monthly subscription since I can always keep most of my current Pokemon on PokeBank and because I probably won't need the extra storage space until Gen 10 or so.
Either way, premium is unlikely to be needed as a yearly subscription for most of us and will most likely be bought in monthly or possibly quarterly amounts in order to transfer over new Pokemon every now and then, rather than to be used constantly as a storage.