I've not had any issues with getting shipping quotes by using the keys and the API, but I don't know if I can use the plugin as-is. There are no settings in the back-end for any of the Shippo "Extras", like adding in insurance for each shipment. Their API can accept other variables in the array that's passed for both quotes and preparing shipments, but there's nothing available to include except the most basic values required to make a valid call.
The 'Insurance' page from their API docs: https://goshippo.com/docs/insurance/
It also looks like there's only one box size for an entire order in the plugin's code, and it is only using the default value set by the admin, and not a calculated value based on the items added to the cart. It's fairly easy for me, in my use case, to guestimate what a reasonable box size would be and use that instead of a calculation - but - I'm wondering whether the weight total that gets passed (which appears to be the true sum-total of all the ordered item's base-weights) will push me into another weight class with USPS and end up costing me more than I expect - or invalidate the call and not submit a shipment.
I don't collect taxes on anything I list (my items are used, and I'm not a reseller of anything), so I've set up a tax calculation to act as a percentage charge on the basket total price to get the insurance and S/H fees paid for at checkout, but there's no way that I've found to pass on the name/value pairs that Shippo needs to actually insure the shipment.
It would be helpful if there were a few of the 'Extra' variables available under the plugin's settings page to (optionally) accept those additional values. If nothing else, at least those used for insurance... i.e., Amount (my cost, as X.X% of basket's subtotal, currently it's 1.25%) Currency (paid, in USD) amd Contents (what's in the package, in general).