I've been working from home for about ten years, so when COVID happened, it was no real change for me.
Generally, I love it, but I've always worked on and with geographically separate teams, so even when I have an office nearby, I'd only be going to it to be on Zoom/Teams meetings anyway.
Financially, it's great! It's wonderful not having a commute, saves a ton on gas, vehicle wear and tear, and the habit of spending money on lunch. I also don't have to maintain and upkeep as many "professional" sets of clothing.
It's also great for keeping up with house chores, when I take a break to stretch, I can throw in some laundry or fill up the dish washer.
Downsides- work life balance. Work is always there. My work set up is right next to my personal PC set up and when an email comes in after hours, it can be tough to not address right there.