The "I need some place to organize tabular data" use case is so different that I'm not considering it for the rest of this.
But for actual computation, if you throw it in Claude, it'll figure it out. It's much easier to do than to use Excel. Claude itself isn't limited to Excel; it can use pandas and the much, much improved plotting tools compared to Excel. I'm an OpenAI guy myself and used codecs to have it make me ggplot2 graphs, but then I forgot to specify it and it just used straight-up Python — I think it actually generated them as SVG files. As sad as I was about it, they looked better than the ones I had it make using ggplot2.
Regular Excel doesn't even compare there; not only can ggplot2 make many additional types of graphs, but SVG plotting, Python, and pandas can make literally any chart you want, including things like polar-coordinate charts.
Now it'll be harder to do the same for word and harder still for excel, but word is doable, and claude can build one off tools better than excel can, so I definitely think that MS should be wary.