When considering whether "upgrading" your board, you want to consider how it will impact your enjoyment of the game.
Enjoyment of the game is impacted in a few ways:
A hard, smooth, level, and slick surface allows for accurate shots and purer deflections that allow advanced players to use "angles" better then lower quality surfaces.
The rigidity of the posts, and cleaner cut 20 hole provide more consistent bounces and 20 point hits.
A solid, thicker play surface combined with a taller rail supports having harder shots being trapped in the ditch rather than bouncing back on to the play surface disturbing the remaining pieces.
Stained and urethaned wood or composites are less susceptible to moisture, wear and tear and are less likely to warp and/or lose their shape over time. Quality crokinole boards are frequently considered desirable heirlooms and can be enjoyed pass down other generations
Presentation, Aesthetic and Ergonomics:
Many owners of high quality boards consider them artwork or attractive furniture. Over hung on a wall or displayed on a stand, the boards are often conversation starters: you are more likely to play.
Placing a substantial and attractive board on a table with high quality discs definitely changes the look, feel, sound, and even smell (esp a freshly waxed board) that engages players more than a smaller cardboard playset.
If you enjoy crokinole on small cardboard set, and think that this is a game you would be playing for many years, you might consider a handmade board a form of investment. Its not uncommon for players to point to the size and price point of a quality crokinole board as reasonable alternative to a billiard table or shuffleboard table.