I'm hoping for a positive attitude from them.

You shouldn't expect that from a bank who deals with fiat money. They are gonna tell you only about the dangers of dealing with cryptocurencies

For me, it makes much more sense to sell gradually into an uptrend and take profit and then later use that profit to buy back whatever you sold.

I agree with you here but the fact that nothing rises for ever is true and due to what is happening in the market now, you may buy a currency thinking that you bought at a low trend only to wake up one morning to find out that the price gets even lower without any hope of rising again.

Sometimes it's a big big loss