I'm going to confirm that I too have dial tone! I am using a traditional vintage telephone that connects to the router. Someone said earlier in this thread a couple of months ago that I may need a special adapter to get ringtone. I'm not having any problems with receiving incoming rings either!
However, I have unplugged the old vintage phone from the router and just keep it as a souvenir as I can't turn off/mute ringing on that old vintage phone. So it can be a potential problem if there are spammers calling, may wake me up.
But the wireless DV Alexa phone received along with the router is actually a more convenient phone to use as it's not dependent on plugging in the router and can keep it anywhere at home. You can also block nuisance calls and mute ringtone, something you can't with traditional telephones.
It's actually a really magical service! I never thought an old school phone can work with a router. This is certainly amazing technology. But like I said, the major drawback is that you are 100% dependent on a reliable and stable internet connection as well as electricity not going down. If the internet is not stable and you rely on this for important phone calls then it will be a problem.
If your electricity supply is not stable that should be addressed with your electricity company and likewise an unstable broadband line should be complained about to BT.
As regards the electricity going down, while it may not have been a problem with your vintage phone it would have been a problem with cordless DECT phones which required a power supply to the base station yet nobody complained when they were introduced.