I took Tai Chi (Wu Style) years ago from a Chinese exchange student who knew his stuff. It was definitely based on combat principles, but has been adapted as a health regimen. We'd ask him about this move or that, and would get answers like; 'This is universal block. This is dodge of high blow and strike to midsection. This breaks arm.' But also, 'This is just very pretty.'
Tai Chi's major principles focus on energy and movement. Your partner or opponent moves forward, you move back. They pull back, you move forward. The slow motion of practice requires some discipline to go through the forms at a consistent speed. It's considered a good exercise for your internal organs, and a good exercise that can be done at all ages. It's not nearly as easy as it looks. After an hour of work, my legs were sore.
There's an 'approved' Han style short form that is used extensively, but as always, there are are loads of different stylings, based on different training lineages and principles. Among modern practitioners, you can run into all sorts, including flakes who have no understanding of the principles or background, but that is always an issue with any martial arts related practice. Investigating backgrounds of the teachers is always a good idea.
If you are interested in a more vigorous alternative that is still not so combative, you might take a look at Aikido or Ki-Aikido. Lots of rolling, throwing, and a more strenuous style. No attacks, but lots of work on dealing with them. And some cool arm and joint locks. It is very much a reactive system.
