@raum I would guess that most of the people who remove the seeds are doing it to remove the extra moisture (like @ragingloli mentioned) or want consistent texture (like cucumber sandwiches)
That’s me. Seeds are good, I enjoy whole cucumber in sandwiches, in vinegar with onions, etc.
But I also like to make crunchy tzatziki without seeds.
1) Peel and halve the cucumbers, scoop out seeds
2) Cut into crescents about 10mm (3/8”) thick
3) Put the crescents into a colander, mix with a little salt
4) Place the colander into a bigger bowl, weight the cucumber with plastic bag(s) of water to press out moisture for 30–60 minutes
5) Mix cucumbers with plain yogurt, lemon and garlic
6) Mmmmmmmm