Is a hot water storage tank with an integrated heat pump sensible?

My heating engineer recommended a DHWC from Stiebel Eltron for hot water generation. Does anyone have experience with such in-house heat pumps?

There is a district heating connection with decentralized hot water generation using a flow heater and small storage. This is supposed to be replaced by a central solution, primarily producing hot water also through district heating.

That means I also don’t have a heating system in the basement, whose waste heat the heat pump could significantly utilize. The heating engineer also emphasized rather the moisture-reducing effect. (House is from 1960 with a corresponding basement)

If I use such a DHWC, I would probably have to choose the SOL variant to also use district heating as an additional energy source. Otherwise, I fear I would only generate high electricity consumption.

Are there any experiences with the system – also regarding sensibility and economic efficiency?

What I can say is that the "warm water storage heat pump" in our house works reliably - here we gave the installer free rein and got a Vaillant model - a virtually local product, which we agreed upon. I have not yet installed an energy meter and cannot make an exact statement about the economic efficiency. With the installation of the new photovoltaic intelligence, we will direct surplus energy from the roof into the hot water storage.
A connection to district heating is of course sensible.
Instantaneous water heaters are inexpensive to purchase but more expensive to operate. We have those in the "children's apartments." However, these will not be permanently occupied and will later be properly billed separately in case of vacation rental.