With the fast technology advancement and lowering price of plastic sealer, I never imagined there are businesses who still use the old aged plastic sealing technique. Melting the opening with a candle flame. There are cases where alcohol and kerosene lamp are use. The candle and alcohol lamp are fine but kerosene is unforgivable. The food is likely to absorb the foul smell.
Table top impulse sealer can be acquired for as low as 800 pesos and hand-held sealer for 180.
There are three reason why I am against it. I already mentioned the first above. Plastic sealers are very affordable nowadays. The only reason you cannot buy is you never want to.
The second is aesthetic value. It is not pleasing to the eye. It looks cheap. Not unless the producer wanted his product to look cheap.
On the side note: There are cases when customers never wanted buying when the product looks expensive even though the price is affordable. My friend changed his peanut butter packaging to a more elegant PET and his customers declined. I shifted the shape of common cacao tablets (tabliya) to bar style. Then most customers never wanted it.
The third and the last. It is inefficient. It requires a skilled hand to achieved a good seal with a fast rate. Too fast and there will be too many fail seals. Too slow and you’ll never get what you pay for labor.