cost of insurance, gas, the machine, maintenance. minimal costs <$100 a year, probably even if you pay a bike shop to do it. the occasional repair might cost $80. compare that to everything in a car.
health benefits. getting exercise instead of sitting in traffic.
more fun. it is an adventure vs sitting in traffic.
no looking for parking, getting gas, or parking or speeding tickets. huge time saver in total.
car vs commuting on public transportation
in charge of your time / schedule
downsides - you have to go where it is safe to bike
what you have to learn?
how to dress. usually sweat wicking clothes. if it is a nice event, just get there a little early, bring a change of nice clothes, and get ready in a bathroom. done it tons of times...birthdays, meetings, etc.
which routes to take. you get better at it as time goes on, but google maps has a bike function for navigation and usually routes you through safer roads. i prefer a side street or neighborhood street to a fast street. and an off street bike path is better than all of those.