Doing a little research he probably is a pretty good shooter. In 110 career G-League games he's shot 44.9 from 3's on a large volume of shots (692 total 3's taken). In addition, his FT shooting, which is another good way to measure how good a shooter is, is also very high 94.7% this year, 88.8% over his G-League career (232 attempts).
This year he's shooting a blistering 14 for 21 from corner 3's. This is especially important because we simply need a bench wing player to keep defenses honest and create spacing, while a large majority of these wide open 3's come from the corners. Compare his shooting to Semi, who's majority of 3's (66%) have been in the wide open variety (defined as the closest defender being 6 feet or more away), yet he's only shot 28.6% in this wide open variety. Nader, on a smaller sample size of wide open 3's (34%), has been equally awful shooting just 26.7%.
A look at Eddie's good form/quick release during the 3pt shooting contest-
https://www.youtube.com/watch?v=b85Q0Uxh07gI disagree with the OP that we will use him shooting off of screens, curls, etc. There is pretty much no way that the team will be having plays designed to get him open. Instead they'll place him in the weakside corner, like they often do with Semi and Nader, and hope he creates spacing and hits the stand still open 3 at a high rate when called upon. If he does that and is at least decent defensively, then he'll likely get some minutes. Who knows maybe in time he turns into Wayne Ellington. That seems like a reasonable ceiling.