Buy an uninsulated house? Does it make sense?

[*]It is an old house with charm but thanks to an extension from the 80s there is enough space and especially in combination with the location and the plot it is a suitable property for us. [*]The floor plan fits on the upper floor with slight adjustments, on the ground floor we will practically do almost everything new anyway, but it offers enough options. [*]The exterior walls are plastered, not brick. Therefore no cavity or similar. [*]We are actually considering replacing the windows. However, "only" for aesthetic/functional reasons. Energy saving is probably hardly affected because of the uninsulated walls. So it is with mixed feelings, since they are still in very good condition and the overall ecological balance is not good. [*]The base slab (no basement) is presumably(!) partially insulated. We will only know more when we remove the floor. Whether it makes sense to insulate there and maybe even install a large-area underfloor heating is definitely an open question we are happy to consider. [*]My mother-in-law is an architect with a lot of experience in existing buildings. So we feel very well advised in terms of expertise (just as an example: new windows and dew point). But a professional thinks more in terms of a "challenging task" rather than expressing a subjective opinion. [*]At first glance, there is nothing significant to criticize about the substance (stone walls, roof, and wood), likewise the heating system is still quite new and the pipes look okay. New radiators are firmly planned, but not necessarily completely new pipes.

My mother-in-law is an architect with a lot of experience in existing buildings. So we feel very well taken care of in terms of expertise (just as an example: new windows and dew point).

The actual problem that new windows bring in old buildings is usually misjudged by architects...