Top mount sink with no visible sealant
I keep reading that one of the main disadvantages with a top mount sink is that there is a visible join between the sink and the counter top. This seems to be either a silicone or a caulk material. The issue people note is that dirt gets caught in this seal and cannot be cleaned out.
The funny thing is, my parents have had a top mount sink for 20 years, and there is neither a visible sealant nor any hint of dirt between the sink itself and the counter top at all. They just asked their plumber how the sink is sealed, and the plumber told them he used a material like Blu Tack which is underneath the 'lip' or 'rim' of the sink.
Is this an unusual practice? Or have I gotten myself confused with too much research? It seems to fix all of the mentioned issues, but I can't help wonder why everybody else isn't doing this? We've had zero issues with our sink in 20 years.