Well there are several:
1. If you plan on competing in tournaments, there is much to be said about the getting used to the tactile sensation of moving pieces WHILE abiding by the set of rules and norms of tournament-play (touch-move, push-clock etc.)
2. Chess.com does not expose an improving player to some of the uncommon + bad behaviors that one often sees during OTB (over-the-board) play. Some of them include =>
-Blitzing / playing fast during time-crunch situations.
-arrogant players and their shenanigans
-misbehaving kids who slam/abuse pieces/clocks
-distractions such as talking / kibitzing
- People hovering over one's shoulder looking at your games.
=> ALL of which are often present in tournament halls (except for the talking/kibitzing part). If you want your child to play competitively, exposure to these elements (however painful / undesirable they are) is a must. This is not just a game of the mind, it also takes attitude and nerve WHICH cannot be acquired through online play.
3. The "good" social aspect : You meet a lot of people from various walks of life. A vast majority of chess players are friendly + helpful people. Like everything else, a local chess club gives a player a sense of "belonging". Teaches respect and courtesy when winning/losing because the person who you just crushed is not an invisible entity online => it's a real person whom you'll probably be playing again some other night at the club.
4. The teaching aspect : Chess.com and all of the online training materials is one-way traffic in terms of how the student can learn. There is no room for questions or doubts. If the GM on the video tutorial says "blah blah blah" you just have to either believe it or not. You can't ever ask "why not this..."?.
BUT ... .Having a strong player yelling at you at the clubs or telling you why this move is clearly bad or clearly good (this is PRECISELY how I got stronger) makes you improve 10 times as fast as reading or watching people tell you what to do without any room for questions. Most clubs have senior/stronger players who don't mind going over games with you.
5. Notifications about tournaments : All clubs schedule tournaments as well as post notifications/flyers about other tournaments in the city. This makes for a good place to gather information. Sure, they could also be posted online but I've noticed that a lot of clubs are still pretty old-fashioned about using the internet as a medium for broadcasting tournament information!
Hope this helps!
Shivsky
I am looking into local chess clubs for my 13 yr. old daughter. What are the benefits of joining a local one? Seems like we have an outstanding virtual chess club right here.