Do you mean bunkers? Because it works quite well with nip07 and nip55 signers. It can work with bunkers (nip46) too, but you have to load (and decrypt) messages by time. Thankfully most feeds are by time.
Discussion
With local relays bunkers also work quite fast, not as fast as nip 55
We are talking about many orders of magnitude difference of performance. With giftwrap you would have to have multiple rounds trips just for a single wrap (wrap, seal). This is a lot different than processing thousands in parallel on the scale of milliseconds.
If we are going to be DoS resistant it needs to be crazy fast.