When I was recovering from my recent illness and bedridden for several months, I wore no watches and got along just fine using a simple two hand quartz wall clock in my room.
Actually, in the snooty rarified atmosphere of the highest end timepieces (the kind that start in the six figure range!), anything more than an hour and minute hand is considered to be a "complication" and actually a blemish on the "purity" of the timepiece.
Personally, I like to have a second hand and a readable date on my watch at a minimum. The second hand lets me know its still running and the date is important because I NEVER have a calendar handy when I need to know the date. This is the minimum I need to feel informed enough when wearing a watch.
A day complication also can come in handy. I have a friend that went camping for a week this summer and when he returned he told me that the next watch he buys will definitely have the day of the week shown on it. Why? Well, it turns out that when camping for several days, it is very easy to lose track of what DAY it is!
On VERY rare occasion, a chrono complication can come in handy. Unfortunately, the chrono subdials on most watches are virtually unreadable, distract from the watch's main function, and, through the pushers, can adversely affect the water resistancy of the watch's case. I've only owned one watch in the past that had a digital chrono function on it. I did use the function as meetings to time how long each person could speak and it was readable. I recommend this type of chrono for anyone who actually needs one. Best of all, they can be accurate to 1/100 of a second.
Anything beyond this is, IMO, purely of interest to those who like gadgets to play with. Admittedly, watches, after you've noted the time of day, can get a bit boring. No matter how attractively styled, they basically just sit on one's wrist. But, a watch with plenty of buttons to press and strange looking dial indicators / symbols is more fun to watch. This is probably one of the reasons I am so fascinated with the tourbillon movements. There's something about seeing that revolving escapement that I find hypnotizing.
so, "purity" be damned. Get whatever features you want on your watch for whatever purposes YOU deem necessary. If you actually use the complications, then fine. If you just like to watch and play with them, that's fine, too.