This rankles my inner bitmap purist because of the loss of fidelity incurred with each transformation of an image.
No matter what the source of the image, vector or raster, the Cloud processing is going to re-rasterize it to match what is required by the laser. Not only is it going to reprocess the vertical line spacing, it is going to reprocess the horizontal dot pitch based on the speed of the engraving.
As @chris1 points out, if you render to a high DPI, like 600 (and probably even 300) the cloud servers will have enough information to filter the image to achieve a very good result.
The type of transformation that would severely degrade the image would be an older style of processing that used pixel-picking (picking the closest pixel to the target) rather than interpolation or filtering. Also, to be able to see pixelization in the output you would typically need to be starting from, or going to, a much lower resolution.
Using bilinear filtering, the value of a pixel being output uses information from above, below, and to either side of the fractional pixel position that represents the location in the source that corresponds to the position in the destination image. Depending on the exact filters being used, it may take into account information from several pixels away from that location. Video game consoles do this same kind of thing when they cannot run a game at the highest resolutions. They will create a lower-res image and then scale up to the final HD image. You cannot really see the original pixels in the output. Things are just a little fuzzier than if the full-resolution image could actually be created.
All that said, there might be a slight difference in quality if you were able to flatten the SVG so that all of the cut-outs were properly subtracted from the paths. (There are a number of threads here about doing that–I’m a n00b on Inkscape and Illustrator, so can’t help there). The resulting raster created in the cloud would be created with as much precision as possible. But I doubt you’d find a noticeable difference and just doing as @chris1 suggests is likely much easier.