How does Bloomberg Barclays US Aggregate Bond compare to ICE US Treasury Core Bond?

They have different constituents. The ICE US Treasury fund consists of only US Treasuries:

The ICE US Treasury Core Bond index tracks US Treasuries. Time to maturity: At least one year

while the Bloomberg fund consists of treasuries, other gov bonds, and corporate bonds:

The Bloomberg Barclays US Aggregate Bond index tracks USD denominated fixed rate bonds including Treasuries, government-related, securitised and corporate securities. Rating: Investment Grade.

You should expect higher return on average from the Bloomberg fund, but also higher risk (in terms of fluctuations) because of the credit risk of corporate bonds and securitized products (e.g. Mortgage-Backed Securities).

BTW do not go by the fund price to gauge whether a fund is "expensive" or "popular" or not - fund price is largely irrelevant since you can buy fractional units (you can buy 100 EURO of either funds just as easily). What matters is the expected return and the expense ratio.