[gruez]

>You're getting bottom-of-the-barrel capacity that (even if it works) is so slow that you'd be lucky to even use up half your data cap. You are always roaming and your data is tunnelled through what feels like some dial-up modem in some shady warehouse. These are a scam.

>I've tried a few of these and can rarely pull more than a few megabits per second (in a location where a carrier's own SIM pulls 150+).

That seems.. fine? If you're traveling and your use case is checking google maps, or logging into airbnb to pull up your booking, you don't need 150 Mb/s of speed and low latency. The only case where it might be dodgy is if you're doing voip calls or watching streaming videos, but why are you doing those things on vacation? Sure, it'd be nice to have a local sim with low latency and high speeds, that's often much more expensive than esims and/or comes with more hassle (eg. KYC or having to pick up the sim in-person).

[Nextgrid]

You are severely underestimating the amount of JS and other tracker SDKs competing for traffic in the apps you mention. Browsing modern apps/websites on an unreliable 1Mbps connection is not pleasant, even more so when you're in a foreign country and rely on it to find directions/translate/etc. Not to mention if you suddenly need to download a local taxi/etc app that's 100MB.