Regarding this question, there is an advice in Attack and Defense by Ishida and Davies that wonder about.
At least two times (diagram 8, page 14 and diagram 8, page 26) they suggest that after making a lot of potential territory, the corner should be closed, as in the diagram below.

Click Here To Show Diagram Code

[go]$$Wcm1 Attack and Defense, page 26
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . X . O . . O . . O . X . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . X . . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . 4 . . . . . . . . . . |
$$ | . . O , . . . . . , . . . . . , . . . |
$$ | . . . . O . . . 2 . 3 . . . . . . . . |
$$ | . . . . X O . . . . . . . . . . . . . |
$$ | . . O O O . O . X . 1 . . . . . . . . |
$$ | . . X X X X X X . . . . . . . . . . . |
$$ | . . . . . . . . . X O . . . . . . . . |
$$ | . . O O O O O O O O . . . . . O 5 . . |
$$ | . . X X X X X X X O . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

I did play such a move a few times. But while it is nice to have a big territory, it also made me a bit ashamed, since it looked rather slow and clumsy. Is such a corner enclosure really a good idea?

Looks a good move to me: if you don't play there and black gets a chance to 3-3 which side do you block to avoid feeling sad? It makes the bottom side (about a 3x10 block) almost solid territory, and with another move on the right side you could get a bunch more side plus centre and black doesn't have the easy way in at 3-3. If by clumsy you mean having 2 stones next to one-another as an isolated iron pillar looks a bit silly (versus says a 3-4 5-4 shiarmi) then yes that's true, but also it's solid and black doesn't have so many forcing moves against it like attachments or peeps. Kim Seongjin 7d played a move like this in the Vienna tournament which I liked: see move 47 on 2nd branch at move 1 at forum/viewtopic.php?p=221574#p221574.

Okay, maybe I should try to embrace the lonely iron pillar shape, even if it goes against my wish to play cool moves.

The move by Kim Seongjin does not look so silly as in the diagram above though, since there is an enemy stone nearby.