Gambling is gambling to start with, it doesn't matter if it's online or traditional.

Most of the arguments seems to tackle about the conveniences and accessibility. Well, valid or not. There are pros and cons for the said gambling genre.

Online Gambling
Pros:
1. Easy to visit/access
2. Player can set his/her ambiance
3. Less restrictions
4. Can set limit? (Depends on the gambling site if they have safety feature like this)
5. Varieties of game
and etc,

Cons:
1. Poor support (Prone)
2. Site Breakdown
3. Prone to scams, hacks, phishing
4. Limited access (Varies on which countries)
and etc,

Traditional Gambling:
Pros:
1. Loyalty benefits
2. Free drinks/food (depends)
3. Chance to meet new people
4. Casino rewards
and etc,

Cons:
1. Poor ambiance (Foggy place due to cigarette smoke)
2. Less control on spending
3. Syndicate prone (Loan sharks)
4. More addictive (high chance)
5. Not that accessible to all
and etc,

There are still a lot to compare, but one thing still connect both, which players  are always the loser and the owner of both gambling site/casino will always be the winner.