Yeah, I didn't realize what an enormous difference this made until I ran the numbers.
In your example above, let's say the person purchased those 10 Meta shares for $38 each at the IPO and they're worth $322 each now. That's $3220 in proceeds and a $2840 capital gain.
The taxes on this depend on income level and state of residence, but let's say they're in CA making $300K/year. They'll pay 20% federal capital gains tax + 3.8% net investment tax + 10.3% CA income tax, or $968 in taxes, and they're left with $2252.
On the other hand if they donate the shares to a charity (or DAF), they get a tax deduction for the appreciated amount ($3220), which can be taken against 35% federal income tax + 10.3% CA income tax = $1459.
So in the scenario where they just sell the shares, the proceeds after taking taxes into account are:
Donor $2252
Charity $0
And in the scenario where they donate the shares, they are:
Donor $1459
Charity $3220
In other words, for an effective cost to the donor of $793, the charity gets $3220.