No idea about the club supplement, but you're welcome to PM me if you want the email address of the front office manager.
Just completed a 4-night stay here. App was showing an upgrade to a Premium City View Club Access or something like that, so I think the room categories in the Wiki may be outdated. I don't understand what they consider the preferred view here; mine was toward Hankyu station, but I think I'd prefer being right above the front desk; it's stunning at sunset. Anyway, room was just a few doors down from the club lounge, and quite similar to pretty much all the rooms I've had here over the years, whether RA, Spire, or now Diamond. Rooms are still very nice, but of course the hotel is no longer brand new.
I had access to the lounge via milestone lounge pass. It's one of the best lounges in the system. Lounge breakfast has a choice of 6 hot items made-to-order, and a small buffet. I picked the steak every day, which can't be more than 60g (2oz), but it was tasty. In addition, you can order eggs, hash browns, sausages, miso soup, etc. Interestingly, unless you specify, everything comes out on individual plates -- giant plate for tiny steak, smaller plate for hash browns, small plate with two sausages, etc. Oh, and it also doesn't necessarily come out at the same time; I had hash browns and miso soup as a sort of starter. Instead of having breakfast at the club lounge, you can take it at the main restaurant. I went there just once, and it was a zoo, with waits for tables, people piling their plates up high, stuff running out. The lounge is a far more relaxing environment.
The lounge also offers afternoon tea from 2:30 to 4:30 -- I mostly just selected a few sweet items here, but once ordered the full tray. Evening happy hour runs from 5:30 to 7:30 and has champagne, 3 hot items brought to the table, and a small buffet. All high quality, tasty stuff.
After a break of nearly 4 years due to Covid, it's certainly nice to be able to visit Japan again. One of the joys is the occasional weirdness, and I'd be remiss if I didn't mention this episode at IC Osaka. At check-in, they tried to take a deposit and my credit card was declined. It had worked a few hours prior at IC Strings, so who knows what was going on. They said they'd try again later. I'm on a points reservation, so I immediately forget about this. Next morning, I walk through the lobby, front desk manager chases me down. We try the card again, declined. I have a dozen+ cards in my Apple Pay, but only one physical credit card plus two physical debit cards. I'm also making a large purchase, so I have wads of cash. I offer the debit cards. Can't take a deposit from a debit card. I offer cash. Can't take cash for a deposit. Ok great, have a nice day. In the afternoon, the club manager approaches me. We haven't been able to take a deposit. Now, at this time I had already racked up a laundry charge of 998 yen, so obviously they're starting to get worried. I once again offer debit cards or cash, nope, cannot, "we will monitor your consumption and may ask to make a prepayment." I call Chase -- it turns out, the transactions were declined because they swiped the card, rather than inserting the chip. I go back, tell them, ooooh, it works! Now, let's say that even if this is somehow my fault (for only carrying one credit card and not telling them to insert the chip), isn't it a little weird for an international hotel to keep hounding me over a deposit? I offered cash -twice-, you declined, so it's time to let it go!
Overall, a great hotel with an outstanding lounge!
Afternoon tea set
Afternoon tea -- just sweets
Evening hot items (brought to table)
Evening cold items (self serve from buffet)
Breakfast steak