Major consumer speaker vendors don't make it easy to compare speakers. When I was looking for a portable speaker to play outside I was surprised to see that for most of the speakers you'll find at big box stores, there are no statistics for loudness or how it sounds. The best we get is size and rarely amperage, which I found through trial and error are dubious measures at best. I ended up returning two overpriced soft sounding speakers before the third one was sufficient. Price doesn't make as much of a difference as I thought it would either.
As a consumer, I don't know what to trust because the marketing on these things can be pretty useless.
There's no great way to measure power output for an amp, surprisingly. The old FTC rating system was something like continuous wattage at a fixed voltage at all audible frequencies. This was decent, although actual music isn't anything like white noise. =)
So manufacturers give absolute BS "power ratings" like "40W" which usually means the amplifier can produce that much output, at a single frequency, for a zillionth of a second at 10% distortion which doesn't much resemble real music either.
But even if they were truthful about the rest of that, it wouldn't matter because knowing the power output of the onboard amp is useless without taking into account the efficiency of the speaker drivers themselves.
As a consumer, I don't know what to trust because the marketing on these things can be pretty useless.