I can see why you say that. And FWIW, I really don't care if he develops power or not. If the power he has is gap to gap and he can stretch doubles into triples, that's great. I really don't care how often (or not often) he knocks the ball over the fence.
Tony said that the pitch recognition/strike zone judgement is above average, which is more important to me. SG seems to think that pitchers are going to challenge him more if he's not a power threat and I can see why he says that but I disagree a little bit. If the speed is that legit, if the base stealing threat is that legit, he's still a threat...just a different type of threat. They're still going to try to get him to chase out of the zone, they're going to try to make him get himself out, which is why the pitch recognition and plate discipline is so important. If they throw strikes and IF (a big if) he can get the bat to the ball, then he's still a threat to beat out a grounder, take an extra base, etc.
But in this day and age where stealing bases is encouraged, we just saw Ronald Acuna steal 70, IIRC it's been awhile since anyone has stolen that many. So what could we expect from Bradfield? It's hard to say but I think it's safe to say he's going to be a terror on the basepaths. Like I said, I don't care about the power, his offensive game is about getting on base and stealing bases, that's where he's a threat. The lack of power, IMO, doesn't matter.
Brett Butler is an interesting comp though, I am not sure how welcomed he'd be in this day and age. IMO, he's a bit of a forgotten player, he was one of the better leadoff hitters in the 80s and 90s, I hardly see him mentioned anywhere these days. But if Bradfield's career turned out like that, I'd be really happy with that, too.