Speaking personally, I want to own as much equity as possible in a company I start. 3% is a ridiculous amount of common stock to go towards something like this.
3% of all my companies to date is worth exactly zero.
The idea isn't to say "everyone should throw X%" into a pool. It's for you to pick a number that makes sense for you and find a group of founders that wants something similar.
Founders who are absolutely certain of their future success only do worse by pooling equity. The more likely you are to succeed and succeed big, the less likely you should be to contribute to a pool.
Luckily, founders run the gamut in both skill and risk tolerance, so there are probably people close to you no matter where you fall on the spectrum.
And giving away a big chunk of equity like that is a signal to future investors, employees, and partners that you think 3% of your current company will be worth something similar.
Speaking personally, I want to own as much equity as possible in a company I start. 3% is a ridiculous amount of common stock to go towards something like this.