Good machine and clarifications for those who doubt!

After reading some reviews there are things I want to clarify:
- 2 welds levels does not mean that there are two welds but welding is done in top and bottom of the unit or the 2 sides of the bag and not on one side only; and luckily saw the thickness of the bags.
- This machine is not compatible with 1st prize bags or not intended for this use. You can not use those of the brand (or those of other brands using the same process and that are not cheaper). Since it is preferable to use good references ink cartridges, brand printer, for beautiful photos; Yes it is better, if we want that the machine works well to use the bags of the brand, otherwise there may be surprises.
- In case of doubt that the vacuum is done well, I recall that this device has 3 buttons, welding, vacuum / welding and also only vacuum, so it is easy to empty and after welding, even press repeatedly on the empty button. But normally with good bags, placed in the right place in the device and the properly arranged food inside bags, the machine sucks until the vacuum is done completely.

Knowing that for optimum food preservation 3 points are essential, dry, area and light, why the brand does not offer opaque bag?

PS: I still managed to close the bag original appetizers cakes with this machine and even if I press 2 times the vacuum button, the result was empty and welding quality, great!