They all ask you for your bank info cuz you need to transfer money in just like a stock exchange. Coinbase is at your own risk. I got some money on there mostly bitcoin but not huge amounts. Go thru the Reddit and you'll see countless people complaining. It tends to freeze up and shut out users especially when times of heavy trading. I've seen numerous times where I tried to log in and it was down. Far as your investment, all up to you. It can rise to 50k or drop, who knows. What you invest would be your percentage of a coin so just know you not getting 1 but like 20% or .20 of one or whatever the math is at the price you buy. Lots of institutional buying going on right now which might be causing the price increase, that plus devaluing of USD. If you're gonna go all in and hodl, look into getting a hardware wallet. Mine is from Ledger, which is kind of questionable now due to a data leak but I think there are a few others. Long as you dont fall for any phishing scams or give out any password or anything, you'll be ok. Its a risk just like stocks.
Just don't venture into the bitcoin thread for more info cuz it's complete fukkery at times in there and you might get overwhelmed with all that. It's nothing like in here.