Intergrain Exterior UltraClear on End Grain Coasters instead of Polyurethane?

I used Intergrain Exterior UltraClear (Marine Grade and WaterProof and non-yellowing) on my garden bench without issue.

https://www.bunnings.com.au/intergra...inish_p1520102


I've just used a box finished technique called Hard Burnishing on a number of Coasters.
Some of which are End Grain Coasters and the others are Long Grain Coasters.
This technique is supposed to make it waterproof.

But since these are coasters and not boxes I have a query.
Could I use Intergrain Exterior UltraClear (already purchased) on the Coasters instead of Polyurethane ($60?) ?
And would I use the same technique?
i.e. 220 grit sanding | first coat | 400 grit sanding | second coat

Thanks in advance

Yes it will work but one issue I can see is that of what is technically called block resistance. This could be an issue if a hot cup is placed on the coaster and the more thermoplastic nature of the exterior clear would not be as good in this regard as a crosslinked polyurethane coating.
Cheers,
Paintman