While this will work, wireless ac 5ghz bands may not have as strong a signal as older 2.4ghz standards. I've found it to be better to use a seperate ssid for devices that can use 5ghz ac to force it to use it. Using the same ssid for all your bands can cause your devices to connect to the 2.4 ghz bands as 2.4 ghz call be detected as a stronger signal. If imagine the same is true of ax bands. For the most part, the difference in bandwidth makes up for the somewhat lower signal strength at my home.
That said, unless your internet is fast enough to make use of wireless ax speeds, the only improvement you will see is when transferring data within your home network. I probably won't make the switch to ax unless faster internet becomes available in my area or my current ac router dies and I find a good deal on one.
It seems most IT guys say Band Steering is the preferred method for dealing with this. Yes, 2.4 does a better job of penetrating walls and stuff. Band steering will help favor 5GHz, but still be able to switch to 2.4 if the signal gets too week. My access points allow you to set the aggressiveness of the band steering, I think it is a fairly standard feature of most modern routers and access points. That being said, I still typically set up 3 SSID's - A general one with both bands (and utilizing band steering), and one each for 2.4 and 5 that I use mostly for testing purposes. I also have some WiFi Infrared transmitters by Broadlink that seem to have a problem connecting to a dual band SSID and will only work on an isolated 2.4.
Then again, if you know your environment, and how your 5GHz signal works around your house, and you want to be sure you are only using 5GHz, it may not be important what method is technically preferred. I did the same thing for years. Just adding another perspective to the discussion.